3.9 V8 ran hot yesterday....what now?

[LRJim]

Hey All
Bit of a long story
During a quick squirt out in talarook forest yesterday the old girl got pretty hot. I think it's had a slow leak somewhere and has only been getting water top ups.
I had driven about 80 ks to my sister's in tallarook chilled out for a bit then went out. I checked the oil and water at my sister's before leaving and noticed water around the filler cap. Didn't think to much of it because it still had water.
So we headed out to hit the tracks and it was a fairly long steep uphill run to get there about 20 mins or so. Got to the dirt and found a track it was all a slow climb in low, had no dramas. Next track was steeper and longer a fair bit of work on the old girl. Then out of nowere the temp gauge moved ever so slightly, I'd never seen it rise above the little waves on the gauge. Now I know the gauges are fairly usless so I stopped at a flat and noticed a tiny bit of steam, popped the hood and it was coming from the expansion cap only. Still had plenty of water though, so I let it rest for a few mins. Then we pushed on and the track just got steeper and rockier, pretty difficult with my current setup no lift and that wheels scrubbing. Temp gauge rose up more so I kept on stopping when I could, in the end it got up near the top line but i didn't let it sit there. It never went above in the H area. We had to turn around because the track was getting brutal and I was getting hot. I managed to get down fairly quickly I had too get back to the road stopped once or twice on the way down.
Got to the road still no steam from the engine only the expansion tank. I let it cool for a few minutes and put another 4ltrs in it. I'm hoping it's just steamed out of the expansion tank (high hopes) and not leaked into the block. Engine sounded a bit touch and go for a second but it come good ran fine nice and smooth.
Drive back to my sister's all downhill awsome had no problems at all the disco ran like she should. Got back to hers no steam, topped up the water and left the car on with the heater running no dramas. Drove home 80ks cruising along at 100-110 no dramas. It's an auto and the trans warning light never came on either.
So where do I go now?
I didn't see any water on the ground, oil in the water or milk under the cap.
Is it worth putting a chemi weld product in or is it a no go with these engines?
The waters gone somwere but could it have just evaporated out of the expansion tank because it was just water?
Do the Welsh plugs need changing regularly?
I'm using full sin oil by mistake could it be heating quicker?
Do I just flush and fill with coolant get an aftermarket gauge and hope for the best?
I don't know where I should start looking with these engines summers coming I don't wanna get stranded because she's cooked on me.
Thanks for reading
Cheers Jim

[theelms66]

I would start with radiator removal and professionally cleaned. Is this viscous fan sound like its working ?

[rangieman]

Time for a viscous fan check id say[bighmmm]

[LRJim]

That's what I was thinking it spins but I dunno if it engages when hot. What about installing an electric fan?

[rangieman]

That's what I was thinking it spins but I dunno if it engages when hot. What about installing an electric fan?
Why when the viscous fan is working they work well [wink11]

[DAMINK]

Yea obviously it should not be getting that hot even if offroad this time of year.

Comp test, radiator flush and check fan or replace with electric (thought of doing the same)

These engines dont like hitting the red mate. Warped head is normally the result.

Fingers crossed you were onto it quick enough.

[LRJim]

Why when the viscous fan is working they work well [wink11]No worries I won't bother then. I changed my 250 xflow to take strain off the engine but it's a 6.

[LRJim]

Yea obviously it should not be getting that hot even if offroad this time of year.

Comp test, radiator flush and check fan or replace with electric (thought of doing the same)

These engines dont like hitting the red mate. Warped head is normally the result.

Fingers crossed you were onto it quick enough.Yeah I've been weary of it it getting warm, I'm hoping I caught it quick enough she still purrs. Id still like to know where the water went hopfully just out of the expansion tank!

[Mick_Marsh]

I think it's had a slow leak somewhere and has only been getting water top ups.
Hmmm.... Familiar story. I had that with the Camry.

The waters gone somwere but could it have just evaporated out of the expansion tank because it was just water?
If a cooling system looses coolant (yes, even if it is just water), there is a problem.

With head gaskets, in my experience, they first start with little losses of coolant. They then get really bad really quickly.
That's what happened with the Camry. That is what your story sounds like.

I'd pressure test the cooling system and compression test the motor. See what you've got.

[Mick_Marsh]

That's what I was thinking it spins but I dunno if it engages when hot. What about installing an electric fan?
I put electric fans on the stage 1. I had more overheating issues with those. Viscous fan works fine.

[LRJim]

If a cooling system looses coolant (yes, even if it is just water), there is a problem.


Yes but I'm wondering if it's just bubbling out of the expansion cap? That's the only evidence I've found. No steam coming from exhaust or any other usual head gasket symptoms. But i havnt checked the welsh plugs yet gonna go out soon and look for some evidence.

[Mick_Marsh]

Yes but I'm wondering if it's just bubbling out of the expansion cap? That's the only evidence I've found.
Yep. Same story with the Camry.
It could be that the head gasket is blown between the cylinder and a water jacket. This would cause these symptoms.
If you had the coolant analysed, I suspect it would have exhaust gasses in it.
It sounds like it is in the early stages. Time to take stock as to what you have got. Do a cooling system pressure test and compression test. That will tell you more or tell you to look elsewhere.

I know of another 3.9 that is overheating for inexplicable reasons. AFAIK, the compression test and cooling system pressure test tested ok.

[discomatt69]

I have had the same issues in the past, if the temp gauge moves its to hot, once they start to go up there is a issue, if all is good they never move from normal regardless of conditions.
First things first, if you have done any bog holes or muddy tracks very carefully check the radiator for mud in the fines, I now avoid mud like the plaque but used to play pretty hard... always cleaned the mud out but the fan side of the radiator was chockers and caused overheating as soon as it was hot weather or the car worked hard. The only real way to check this is remove the fan shroud and fan or the radiator.
Given it is fine at 80-100 and cruising it would be that or the fan is not locking up, if the fan is working properly when started from cold it will be fully locked for a short moment and you will hear it roar, same when its hot, you can hear the fan fully locked up and it sounds like a jet engine. If working properly they suck more air and work better than electric fans.
If the radiator and fan are both in working order check thermostat and water pump are good

[LRJim]

I have had the same issues in the past, if the temp gauge moves its to hot, once they start to go up there is a issue, if all is good they never move from normal regardless of conditions.
First things first, if you have done any bog holes or muddy tracks very carefully check the radiator for mud in the fines, I now avoid mud like the plaque but used to play pretty hard... always cleaned the mud out but the fan side of the radiator was chockers and caused overheating as soon as it was hot weather or the car worked hard. The only real way to check this is remove the fan shroud and fan or the radiator.
Given it is fine at 80-100 and cruising it would be that or the fan is not locking up, if the fan is working properly when started from cold it will be fully locked for a short moment and you will hear it roar, same when its hot, you can hear the fan fully locked up and it sounds like a jet engine. If working properly they suck more air and work better than electric fans.
If the radiator and fan are both in working order check thermostat and water pump are goodWell it was the 1st time it's ever moved, it had a big day towing a trailer earlier on in the day then the drive to my sister's. No time to cool then a hard up hill drive to the forest then even harder hitting the tracks.
I noticed a little bit of wetness on the drivers side of the firewall towards the back. Is there a Welsh plug near the trans dipstick? It could be splash up though.
I'm gonna pull the radiator out and clean it properly I'm always on dirt roads and have had the headlights under the mud a few times. I've rarely heard the fan engage I know exactly what it sounds like so maybe that's a problem. I think it was doing it's job but I can't hear **** from inside. Need to find out temp it engages and test off the sensor with a multi. My old rodeo had a viscous fan that was always engaged, kept it running a few thousand ks.
The disco still runs well so hopfully i caught it quick enough
Cheers

[LRJim]

Reading RAVE it seems to have a drain plug where it looks like it's wet I think I'm gonna check that 1st.

[AK83]

I'd doubt it's a head gasket(for now), otherwise you'd have had issues before and after.

Going by your scenario, as the other's have said, viscous and rad.

Rad flush may not actually helps in some instances.
I have a story where I thought I flushed my Tdi's rad when all water came out clean, but after trying the CEM flush stuff, it came out murky again when used as they instruct too.
That is, I ran with straight water for a short time to keep an eye on water colour. It stayed clean, and when I had the time I looked for various options. Added the yellowy looking CEM rad flush ran for a day(they say less, but that's just how it ended up for me).
The now yellowy/green water came out brown murky crud when bottom rad hose was pulled.
Ran hose through system again and more brown murky water came out.

I don't have a V8 of your model(mine is a '00 D2), but viscous will be locked for a good minute or two from a stone cold startup, and you hear it well and good.
It then decouples so the airplane taking off sound disappears. then obviously as it reaches it's coupled temp again it locks itself up and your Disco sounds like a jet plane again! :p

I used to use a cold store riggers glove to hold the fan with the engine idling at operating temp. The padded glove stops getting fingers chopped off!.
Hold fan, get a helper to start engine when hot. You could try to stop it whilst the engine is idling, but there's always a chance that you could break fan blades or more importantly hurt self.

But if I were in your shoes(or car) I'd be totally sus on the viscous initially.

ps. get a temp gauge too. I suspect that if your temp gauge 'just moved' then coolant temp probably touched over 110°C.
There are probably a million and one ways to fit a coolant temp probe and I've so far tried two.
First try was a total shambles and I'm too embarrassed to describe it, but second try was using a brass plug with a tapped hole, not quite made for the job, where the NPT threaded VDO sender fitted into.
I recently contacted the MadMan local contact and purchased much better fitting brass bungs with made for the job NPT thread.

[LRJim]

I'd doubt it's a head gasket(for now), otherwise you'd have had issues before and after.

Going by your scenario, as the other's have said, viscous and rad.

Rad flush may not actually helps in some instances.
I have a story where I thought I flushed my Tdi's rad when all water came out clean, but after trying the CEM flush stuff, it came out murky again when used as they instruct too.
That is, I ran with straight water for a short time to keep an eye on water colour. It stayed clean, and when I had the time I looked for various options. Added the yellowy looking CEM rad flush ran for a day(they say less, but that's just how it ended up for me).
The now yellowy/green water came out brown murky crud when bottom rad hose was pulled.
Ran hose through system again and more brown murky water came out.

I don't have a V8 of your model(mine is a '00 D2), but viscous will be locked for a good minute or two from a stone cold startup, and you hear it well and good.
It then decouples so the airplane taking off sound disappears. then obviously as it reaches it's coupled temp again it locks itself up and your Disco sounds like a jet plane again! [emoji14]

I used to use a cold store riggers glove to hold the fan with the engine idling at operating temp. The padded glove stops getting fingers chopped off!.
Hold fan, get a helper to start engine when hot. You could try to stop it whilst the engine is idling, but there's always a chance that you could break fan blades or more importantly hurt self.

But if I were in your shoes(or car) I'd be totally sus on the viscous initially.

ps. get a temp gauge too. I suspect that if your temp gauge 'just moved' then coolant temp probably touched over 110°C.
There are probably a million and one ways to fit a coolant temp probe and I've so far tried two.
First try was a total shambles and I'm too embarrassed to describe it, but second try was using a brass plug with a tapped hole, not quite made for the job, where the NPT threaded VDO sender fitted into.
I recently contacted the MadMan local contact and purchased much better fitting brass bungs with made for the job NPT thread.From memory the viscous come on at startup, im pretty sure it comes on in traffic. Can you pull them apart and refill refill the silicone in them or are they just a throw away part?
Well I've flushed it with a product and ran it for about 40 mins the bottle said 1hr max.
Ive flushed it 3 times with water now and it looks pretty clean, that bottom hose is a pain to get to. Just need to refill with coolant now.
I'll definitely be getting an aftermarket gauge of some description, I really wanna rig up my android and use rovergauge permanently.
But a small digital one like a turbo timer would be great.
Cheers Jim

[AK83]

.... Can you pull them apart and refill refill the silicone in them or are they just a throw away part?
.....

Not done it myself, but I think I've read that other's have done.

Sounds like it may be OK then. Can still fool 'ya tho.
My D1 kind'a did. I did the (rolled up)newspaper test this time around, where you wedge a paper between the blades, and then the paper through to something else.
The idea is to keep it rigid enough to stop it spinning, but as it gets hot, it then knocks the paper out of the other end and/or cuts through or bends it at the fan end.
Mine didn't budge, and I could freely turn the fan the opposite way even tho I had the engine up to 85°C at the time.

Years back on my RRC, I had the unfortunate experience to have my rad rot itself to dust!
Run fingers mediumly(if that's a word! :D) across fins, mainly middle-bottom to feel how solid they are.

And one other thing I found earlier this year: I posted about it before in other threads.

Noting that I have a digital temp gauge, and is about as accurate as I think necessary(tested against IR temp gun)
I had heating up issues on hot days(>35°C) and A/C running. 40°+ and A/C off, no issue .. kind'a situation.

Ie. the A/C was putting additional pressure on engine/cooling.
Trying to work out why, I did a lot of normal stuff, and then thought to try other, not so normal stuff too.
I assume you know the run up Pentland Hills. That's my normal test run.
Up the hills, on 35° or higher days, I'd easily see over 110°C on the Tdi, 117°C max with A/C on. About 95-97 with it off .. luckily the downhill run allows the Tdi to cool quickly to try the uphill again.
So the not so normal thing I tried was to remove the grille. Max temp on that same day(maybe hotter than my first two runs) .. max temp on the digital gauge I saw was 92-93(two runs) or so. May have been 95 on other occasions, but that same day I saw 110-117, it then maxed at 93 .. just removing the grille.
Stupid me tho, I also play about a bit with injector fuelling, so don't really get consistent results to offer more consistent changes.
Tdi is obviously turbo and the greater effect I noted with no grille was the drop in EGT, from having to back off much earlier when I got to 720°C, to not seeing more than 690° all the way to the level off section. I think it gave me an additional 15k/h at the top due to having to back off with the grille on.

Not sure on the next bit tho, but I don't think it's just the grille that may have caused these differences. Looking at the dreadful electric A/C fans, I reckon these block more air flow than the grille does .. just that removing the grille helped a bit.
So, even having seen 117° on the temp gauge, the dash gauge barely moved at all .. as you noted I reckon just above the wavy line marks. Mine sits a couple of mm's below what would be a centreline.
This coming summer I'm going to test removing the condenser fans(grille on) and see how that goes. if it helps, I'll then have a look into a couple of 10" replacement fans for them .. maybe even a larger single like the D2 uses. Not a lot of room in there tho.

[DAMINK]

Comp test and throw us ya numbers man.
Its the first and most critical step at this point IMHO.
If its a head that just got hot you may get away with a gasket change and shave.
You cook it further and you may have to chuck the engine.

Just pull those plugs and get some numbers mate.

[bee utey]

... that bottom hose is a pain to get to.

The fastest way to drain a D1 rad is to drop a long 10mm hose in through the filler bung and siphon it out. The hose reaches the bottom of the tank no worries.

[LRJim]

Comp test and throw us ya numbers man.
Its the first and most critical step at this point IMHO.
If its a head that just got hot you may get away with a gasket change and shave.
You cook it further and you may have to chuck the engine.

Just pull those plugs and get some numbers mate.I gotta buy a tester 1st I'll get one mid week. Seems to be running fine, no smell or heating up. I'll probably do the heads before summer anyway it will be coming up close to 400k so it will be coming due

[LRJim]

Well I'm pretty sure the fans gone, it just dosnt sound loud enough on startup. And it dosnt seem to come on in traffic either, I remember how loud it was at the lights. My old rodeo had a viscous fan and I remember how loud that was. I had no problems today but it does smell warm and the heater is a bit warmer.
So I guess I'll be in the market for a new one, do I just spend the money and buy OEM? Or is a there a good aftermarket one?
Im getting a comp tester this week but I reckon I'm gonna have head gasket problems. It's getting close to 400k so it probably won't hurt to pull them off. Any recommendations on a gasket kit for the top end? Or anything else I should do while the heads are off?
Cheers Jim

[AK83]

....
So I guess I'll be in the market for a new one, do I just spend the money and buy OEM? ....

Contact Mario(Roverlord).... he has an ebay presence, but better to PM him via here.

About $100(maybe a smidge less) .. but dunno.

[DAMINK]

Make sure you get new gaskets obviously, but the valley and rocker covers also. (Kits are pretty cheap through).
Make sure you get new head bolts as these ones are one time stretch bolts.(again comes in a good kit).
Make sure you have some beers around when you try get the drivers side back head bolts loose.

I would recommend getting the heads checked while they are off, give them a shave perhaps.

As for the fan. **** the old crapper off and put a nice thermo fan there. If mine was playing up thats what i would do. I hate the damn sound of these viscous units.

[LRJim]

Decided I'm going for the thermo fan option. Twin thermo fans from a falcon $50 should be more than enough cooling power. I might be lucky and gain a few ponies.....yea right.
Getting all the gear on my way home from work hopfully smash it all in tonight!
Still unsure if the heads gone it seems to be running fine and no water is disappearing the temp needle still sits under half. A bit smelly so I don't think the fan is doing it's job but no steam thank ****.
Cheers Jim

[barney]

Having had exactly the same problem twice in the life of my 34 years old 110, literally 4 weeks ago fixed it again.
Check the condition of the little fins on your radiator. I've found they rot out about every 12-14 years and while the radiator won't leak, it won't cool properly. It will be fine during normal driving but when you load it up, the temp will start to creep up.
There's only one fix for that, and that is to throw in a new radiator.
Of course, it could also be the thermostat. I have had that problem on other cars but never replaced mine on the 110 since I've owned it (1995).

[donh54]

Once you sort out the problem, ditch the water and use proper coolant. Alloy motors are very susceptible to corrosion using plain water.

[DAMINK]

Once you sort out the problem, ditch the water and use proper coolant. Alloy motors are very susceptible to corrosion using plain water.

Reminds me i should put some of that colored stuff in my car again soon. Seems every time i put the cordial in it wants to leak it out.

[AK83]

....
Check the condition of the little fins on your radiator. I've found they rot out about every 12-14 years and while the radiator won't leak, it won't cool properly. It will be fine during normal driving but when you load it up, the temp will start to creep up.
....

I was going to suggest this too.
I had that same issue on my RRC roughly 15-ish years after it was built. I had it for 5 years at this stage.
On a drive, it suddenly developed a case of the high temps. Had tools and a thermostat with me in the spares kit. Changed that no difference, never lost any water other than that which dumped itself on opening the bungs/caps.
Had a long drive home too.
Got it checked by mechanic, he confirmed tempo sender to be working as per specced(soem resistance measure), temp gauge showed needle in the red, but car never felt overheating, but smelled of coolant.
Not only was is a problem, I drove it like this for 2 years too! never caused an issue. I just assumed the gauge itself just went AWOL.

Radiator was checked, pressure tested etc. never showed any sign of trouble till 2 years later when I was doing some other stuff and rubbed my hand against the lower half of the rad, and the fins turned to finely powered copper pixie dust!

Light bulb moment there and then. Got a new rad, and temp gauge's running into the red area for the past 2 years had come good. As they say ... OOPS! :D
poor little 3.5 V8 .. lived for another 300 or so thousand klms more too [thumbsupbig]

[LRJim]

Got the fan in last night, ended up getting an AU falcon one. I wanted an EL one but the wreckers I went to didn't have any and I couldn't be ****ed pulling one put at pick a part.
I ended up flipping it upside down and attacked the top which is now the bottom with a grinder to get it to fit. It looks good from above and works well but I'm gonna get an EL to get a neater fit.
The wiring is a bit of a dogs breakfast, it needed 2 relays and fuses one for each fan. So they are just floating in the engine bay at the moment. I'm going to pull the fuse box out of VS Commodore wreck I have and make an auxiliary board to neaten it all up. That way I'll have sockets for relays and fuses for lights and other accessories.
The radiator seems alright it looks like an alloy one but it dosnt have too many years left in it. I'm also running coolant even though it keeps ending up on the floor every time I pull the top hose off to **** with the temp sensor. Need an aftermarket temp gauge so I can really dial the fans in right but so far so good!

Cheers Jim

[Rick1970]

When I put EL thermos in my old rangie, replaced sensor in the top of thermostat housing to a lower setting one to activate them, think they also make a dual one so you could run them as two speed if desired.

[Pedro_The_Swift]

I dont know why anyone would replace the original with something less efficient,, but,,
Ford actually do a 16"(17?) single thermo that bolts on,, it covers more rad area then the twins and is newer!! [wink11]

[LRJim]

When I put EL thermos in my old rangie, replaced sensor in the top of thermostat housing to a lower setting one to activate them, think they also make a dual one so you could run them as two speed if desired.I bought a Davies Craig fan controller from SCA it works pretty good just has a dial on it. A lot of wiring involed with 2 fans it needs relays and all that but it's only single speed switch which sorta sucks. I saw online they have a digital version for in the car by the looks, if I keep the thermo I might look at getting that it does a few other things plus has the temp gauge.

[Rick1970]

I dont know why anyone would replace the original with something less efficient,, but,,
Ford actually do a 16"(17?) single thermo that bolts on,, it covers more rad area then the twins and is newer!! [wink11]

This is true, wouldnt do it again, quite happy to leave the V8 Disco with a viscous fan

[DAMINK]

This is true, wouldnt do it again, quite happy to leave the V8 Disco with a viscous fan

There is one simple reason i would not keep them.

THERE A BITCH TO GET OFF!! On the D1 i had to make my own damn spanner to get the thing off!

Surely that alone is a good enough reason to turf it right?

Im all about modifying to make **** easier.

Thermos work just fine and some of them have some good adjustable stuff which is another dial on the dash and we all want that right?

Meh i recon viscous fans are crap. Annoys the hell out of me in the morning actually.



**Also get that comp tester. Good tool to have and it does give piece of mind.

[Pedro_The_Swift]

so,, sort of planning to fail?

anyway if your thermo's last half as long( or shift half as much air--) as the genuine item you can consider yourself really lucky,,, [wink11]

[LRJim]

I like thermo so far but I need to get an aftermarket gauge to see if it's really helping. I got both running now I'm pretty sure on the AU 1 fan spins faster and I kept blowing a fuse. The car didnt get hot with only 1 running today but i was paranoid as hell. The only thing letting it down is the shroud but I'm gonna make one up. Overall fan size I'm still convinced the twin fans cover more area. Looking at the old shroud it was really only in the centre with a heaps of space each side, but it did hang lower than the radiator. But if they can cool a 351 they can cool a rover if setup right.
Do the pros out way the cons....probably not.
I like the idea of putting in a kill/override switch for going through puddles or climbing hills lots splash from the viscous. And if it's like others they don't spin after 2500rpm unless hot, to be able to switch the fan on when towing or going up long hills is always a plus.
It does take strain off the engine but adds strain to the alternator and battery.
Life span well I've never had a thermo go on me but I've had 3 viscous fans die. I'm sure thermos die eventually also.
Noise is a same same, either airplane or loud electric fan sound I prefer the airplane from the viscous.
Viscous is a 1 piece unit which is easy to replace (once you get it off) I ground down a falcon 6 spanner to fit. Thermo is a pain to setup if you go the path I went but you have more control with it.
I like that the viscous is always sucking air through even if it is only some. The thermo is either on or off, I need to set up 2 controllers 1 for each fan.
More money invested in a thermo compared to a cheap viscous.
Hopfully get some photos up soon and a gauge to see how it's actually doing.
Cheers Jim

[Rick1970]

Two switches yes, wire fans through relays so they run in series for low speed, and parallel for high speed.
Keep an eye on the temps in the really hard going stuff, sand, long hills, towing etc......that’s where the extra air shifted by the original fan can become noticeable

[donh54]

Can't understand the problems people seem to have with getting viscous fans off. I have a double ended spanner (via Roverlord, if memory serves - suits V8, Tdi or Td5). One, or at most, two hits with a hammer, and undo by hand. Easy peasy!
As far as efficiency goes, provided the bi-metal spring is clean, and the fluid hasn't leaked out, they work on the temperature of the airflow through the radiator, regardless of engine revs.

[LRJim]

Can't understand the problems people seem to have with getting viscous fans off. I have a double ended spanner (via Roverlord, if memory serves - suits V8, Tdi or Td5). One, or at most, two hits with a hammer, and undo by hand. Easy peasy!
As far as efficiency goes, provided the bi-metal spring is clean, and the fluid hasn't leaked out, they work on the temperature of the airflow through the radiator, regardless of engine revs.I think the issue is most don't get touched for 15 20 years and become stuck. I struggled a little but once i got a screwdriver in place to hold the pulley a whack with a mallet sorted it. My rodeo fan was weird I wasn't really impressed with the way it worked. Has anyone tried pulling the LR ones apart to refill the silicone oil? I've done it before on different cars.
Cheers Jim

[LRJim]

Two switches yes, wire fans through relays so they run in series for low speed, and parallel for high speed.
Keep an eye on the temps in the really hard going stuff, sand, long hills, towing etc......that’s where the extra air shifted by the original fan can become noticeableWell I'm hoping after i fold up a shroud the airflow will increase dramatically. They seem to have heaps of power behind them the only thing letting it down is the shroud. I was thinking of wiring one to come on at 75 and the other to come on at 80 if possible. I'll have to work out how I'm going to power it all withought making a mess of my engine bay. I still like the commo fuse box but it's not really a sealed unit. Gonna have to suss out a different sub board maybe.

[PhilipA]

I once saw a test where the tester dynod a Land Rover with viscous fan and estimated that the fan drew 6BHP when locked.
6BHP equates to about 200AMPs.

Now how many amps do your electric fans draw?

Much to it would seem your surprise this conversion has been done many many times over the years and in many cases resulted in the modifier changing back after an initial drive on sand or up steep hills on a hot day.

What is happening with your aircon fans also. Do you still have them in place? Lots of people manually switch the fans to assist the viscous.

Regards Philip A

[LRJim]

I once saw a test where the tester dynod a Land Rover with viscous fan and estimated that the fan drew 6BHP when locked.
6BHP equates to about 200AMPs.

Now how many amps do your electric fans draw?

Much to it would seem your surprise this conversion has been done many many times over the years and in many cases resulted in the modifier changing back after an initial drive on sand or up steep hills on a hot day.

What is happening with your aircon fans also. Do you still have them in place? Lots of people manually switch the fans to assist the viscous.

Regards Philip AWell going by the fuses its a max of 40amps, I have 2 20amp fuses. I notice them come on at idle but my base idle is too low. I havnt got a switch for the condenser fans yet but if the viscous is as good as everyone says it is then why would it need the extra help lol but I will no doubt put a switch on. I left the condensor fans I'm my racecar and put a switch in, it seemed to help not that it needed it.
Look maybe I will go back to the viscous one day I'm just experimenting. If I do it's no loss the thermos just go into another project and I get a new viscous coupling easy done. Like I said before plenty of pros and cons to both.

Cheers Jim

[Rick1970]

75 is a bit cool, your running temp should be in the high 80’s at least or you may run into overfueling problems. Maybe low 90’s and high 90’s would be better.

[LRJim]

75 is a bit cool, your running temp should be in the high 80’s at least or you may run into overfueling problems. Maybe low 90’s and high 90’s would be better.No worries thanks I thought the 90s were getting in the warmer zone. I'll turn the thermo controller up some more. I was wondering why it was smelling a bit more fuely. Cheers

[PhilipA]

Well going by the fuses its a max of 40amps, I have 2 20amp fuses. I notice them come on at idle but my base idle is too low. I havnt got a switch for the condenser fans yet but if the viscous is as good as everyone says it is then why would it need the extra help lol but I will no doubt put a switch on. I left the condensor fans I'm my racecar and put a switch in, it seemed to help not that it needed it.
Look maybe I will go back to the viscous one day I'm just experimenting. If I do it's no loss the thermos just go into another project and I get a new viscous coupling easy done. Like I said before plenty of pros and cons to both.

Cheers Jim
Most likely the fans are 12 amp each as this is the most common draw.
Just be careful with switching in the aircon fans , as they are about 12 amp and that all adds up to 48amps which is a lot. Actually electric fans do fail and mostly at the most inconvenient time. I had both my aircon fans on my 91 RRC fail at Kununurra and the starter wouldn't turn the engine with aircon on due to the head pressure.! I had to drive home to Avoca only using aircon while moving .
You should also check whether yours actually work.I fitted a Mercedes 16 inch fan (must have been 20 amps or so) to an 81RRC I had in Saudi. It helped a bit but the car still got hot in tail wind at 50C.
I toyed with the idea of Falcon fans but always backed off as I wanted reliability in the boondocks.
Regards Philip A

[LRJim]

Most likely the fans are 12 amp each as this is the most common draw.
Just be careful with switching in the aircon fans , as they are about 12 amp and that all adds up to 48amps which is a lot. Actually electric fans do fail and mostly at the most inconvenient time. I had both my aircon fans on my 91 RRC fail at Kununurra and the starter wouldn't turn the engine with aircon on due to the head pressure.! I had to drive home to Avoca only using aircon while moving .
You should also check whether yours actually work.I fitted a Mercedes 16 inch fan (must have been 20 amps or so) to an 81RRC I had in Saudi. It helped a bit but the car still got hot in tail wind at 50C.
I toyed with the idea of Falcon fans but always backed off as I wanted reliability in the boondocks.
Regards Philip AYes no doubt it will fail at the worst time just like the viscous did halfway through a rough uphill climb. Hopfully if the thermo gos only one dies and I'll have the backup....high hopes. I'm pretty sure the A.c fans work I'll double check now that you said that. I'm gonna do some more experimenting with them. I'm gonna put some cardboard in front of the grille and see if they can keep it cool still. I was even thinking about moving the fans in front of the radiator to see what sort of airflow I get but I don't think it's worth the effort. I will defiantly keep an eye on the draw I'll put in a voltmeter and get all the accessories running and see how the alternator is handling it all. I may try and find a spot to stash the viscous even cable tie it under the car in case I get left out out the middle of nowere with no fans it's an easy reinstall.
Cheers Jim

[Mick_Marsh]

Much to it would seem your surprise this conversion has been done many many times over the years and in many cases resulted in the modifier changing back after an initial drive on sand or up steep hills on a hot day.
Yep. I changed mine back after experiencing Melbourne peak hour traffic on a warm day. The electric fans are now collecting dust in the garage.

[PhilipA]

Yes no doubt it will fail at the worst time just like the viscous did halfway through a rough uphill climb.
I must say in my pretty long experience VCs don't just "fail". They degrade over a long period.
I have learned that I can generally tell if the VC is dying by looking at it.
If there is black **** all over the back of it then the seal has failed and the silicone fluid has leaked out. Of course if you are clean freak and hose any evidence off you will not know.
AFAIK you cannot rebuild them as the thing that lets the fluid out is the failed seal. You could I suppose refill it by drilling a hole and adding some Toyota fluid which I understand is sold by dealers.
If the spring on the front is broken then it is US as the spring lengthens with heat and closes a valve which stiffens it up.
I just thought that one way to test would be to blow a hair dryer or heat gun on the spring and see if the VC becomes stiffer as they usually lock up at about 94or so C.
Of course if the radiator is partially blocked in front of the VC it will not lock up as that part will be cooler.
Regards Philip A

[LRJim]

I must say in my pretty long experience VCs don't just "fail". They degrade over a long period.
I have learned that I can generally tell if the VC is dying by looking at it.
If there is black **** all over the back of it then the seal has failed and the silicone fluid has leaked out. Of course if you are clean freak and hose any evidence off you will not know.
AFAIK you cannot rebuild them as the thing that lets the fluid out is the failed seal. You could I suppose refill it by drilling a hole and adding some Toyota fluid which I understand is sold by dealers.
If the spring on the front is broken then it is US as the spring lengthens with heat and closes a valve which stiffens it up.
I just thought that one way to test would be to blow a hair dryer or heat gun on the spring and see if the VC becomes stiffer as they usually lock up at about 94or so C.
Of course if the radiator is partially blocked in front of the VC it will not lock up as that part will be cooler.
Regards Philip AI've never really looked for the evidence before they go, I've normally noticed that they have died when it's too late. It could have leaked out since I really needed it last. To be honest I havnt even looked at it since pulling it out I was in a hurry. I just noticed it hadn't engaged when I was already hot.
Maybe it's worth attempting to refill it, it's rubbish anyway. There's a good picture of it in RAVE you could work out a good spot. The only other thing is plugging the hole maybe a piece of wire with arldyte or similar same size as the hole. If I can be bothered getting some fluid I'll have a crack. But there's all the other possible issues like the coil and seal as you said.
My old rodeo v6 viscous failed I think I pulled the coil out and it stayed on full time, worked well for a few thousand ks till the head finally blew out at 480ish. Went a long time on 5 cyl before she finally gave in.
Cheers Jim

[AK83]

The usual trick to fixing a failed VC unit was to screw in a couple of short tek screws at 180° locations relative to each other through the VC body.
That locks it up good and proper! [thumbsupbig]

Had to do that whilst on the road with brothers petrol/gas patrol as it overheated all the way from Melb to Mitta Mitta. I ended up towing his trailer so that we could get some movement happening.
Don't ask Nissan for a replacement tho! We found a replacement out in Albury once we had settled at camp a day or so later.
(actually turned out to be more of an ordeal than just the VC tho)

I think I got my Tdi VC for less than $100 from Mario, I see that the V8 one is roughly the same, and I remember the Repco one cost bro a bit more than $150 or maybe closer to $200 .. which I thought was a bit much for a so called common vehicle/part!

So if you were to try to fix 'er up .. I'd say do the tek screw hack.

[PhilipA]

So if you were to try to fix 'er up .. I'd say do the tek screw hack.

Be careful if you have a white fan, as they like to throw blades when going fast and it ain't pretty.
You have to check for cracks at the base of each blade.
The black ones are better as they are glass filled plastic.

Regards Philip A

[scarry]

I once saw a test where the tester dynod a Land Rover with viscous fan and estimated that the fan drew 6BHP when locked.
6BHP equates to about 200AMPs.

Now how many amps do your electric fans draw?

Much to it would seem your surprise this conversion has been done many many times over the years and in many cases resulted in the modifier changing back after an initial drive on sand or up steep hills on a hot day.

What is happening with your aircon fans also. Do you still have them in place? Lots of people manually switch the fans to assist the viscous.

Regards Philip A

Seen that done on many different vehicles.

Why stuff around with what works,put the viscous back on,they aren't that expensive,are generally very reliable,all done and finished.
There is often tell tale oil marks on the fan hub as the fluid leaks out which often causes the failure,so check every service if worried.

Keep it simple and reliable.

[AK83]

Be careful if you have a white fan, as they like to throw blades when going fast and it ain't pretty.
....
Regards Philip A

LOL! Happened to one of my SD1's. Can't remember exactly which one(I've had quite a few) but it had a metal fan fixed(ie. non VC).

Was driving out west near Ararat(260klms from home) and I heard a metallic tingle/bonk/then rattle under the car.
One fan blade had separated dented the bonnet, and flung itself out from under the car. The normally nice smooth V8 went decidedly dieselly on me. very rough idle.
For the first few minutes I couldn't think of what's happened, just never occurred to me that a metal fan would break like that.
To keep car going I had then break a fan blade off the opposing side to smooth out the fan. Kept speed quite low on the drive home.

Fan was off an earlier P6B model as I think parts man Tim reckons the SD1's only had plastic/VC fans.

[DAMINK]

Those aircon fans on the D1 seem to stand up to time ok. And they are in principal the same as thermos yes? Small granted but they do last a bloody long time.

[AK83]

.... Small granted but they do last a bloody long time.

Made by Denso, not some useless UK Co.!! [biggrin]

I reckon they are the main culprit to air flow impediment through to the radiator. The hubs on 'em are far too large considering how close they are to the condenser.
And then there's the silly location of the receiver dryer, smack bang in the middle.

I reckon there's a good reason why they changed the D2's condenser fan to a single larger fan unit.

I'm planning on changing my A/C fans to something less restrictive some day.

[LRexperience]

Ouch.

That the Buick V8 sheds debris (metal/corrosion?) into the radiator passages with the wrong coolant is not new.


The Strange Tale of the Buick Special, Buick-Rover V8, and 3800 V6 > Ate Up With Motor (https://ateupwithmotor.com/model-histories/buick-special-skylark-rover-v8-3800-v6-history/)


Rover V8 engine - Wikipedia (https://en.wikipedia.org/wiki/Rover_V8_engine)

Discovery radiators have narrow tubes which doesn't help.

[LRexperience]

My experience of radiator blockage is switching on of condensor fans in normal driving. Gets worse with time.
Electric fans are hopeless IMO, best setup for Discovery isoriginal setup – radiator in GC, VC fan & cowling.
Typical sign of blockage is cool spots detected by hand on the radiator finsafter a short drive to heat things up. Light spray from hose if too much heatsoak from engine. Can even detect a temperaturegradient across inlet to outlet if blockage. Other option is to buy/ borrow IR gun.
Other problem can be that the blocked zone corresponds withthe aluminium hub of the VC, VC needs airflow to properly engage. Worsens overheatingissue.
Also, if radiator is blocked, coolant seeks out alternatepassages including via the reservoir leading to overfilling & looks like ahead gasket leak.
Over the counter preparations donÂ’t work. Tried it. DonÂ’t like putting hot chemicals inthe aluminium block either. Try boilingcaustic solution in an aluminium saucepan.
After much google research, my fix is citric acid wash of radiator (only). Works for brass/copper versions. Remove radiator, place across two trestles, jugof hot water and teaspoon of citricacid. Shake. Two washes. Rinse well.
Purchase citric acid at Mercedes dealer ( have the same problem)or Woolworths/Coles.
Refill with original coolant for model year.
In my case, Tectaloy long lifegreen concentrate ( type A organic 1065g/l 95% ethelyene glycol)
Checked for neutral pH ( pH7) with pH stick. Some are quitealkaline, OK for cast iron.
OK for a few years, no further blockages.
DYOR

[LRJim]

Alright after a week away waiting for my sub to go through bloody PayPal, I'm back! Got a few things done compression test, fan etc.
Thank you all for the replies whilst I was gone a few interesting comments to go through.
So last week I was installing the thermo, I ended up going to the wreckers to get an EL one. With the EL fan in hand which someone already had taken out for me I was bumming around the wreckers looking at what was in stock, in the distance I saw a D2. Strolled on over and it still had it's fan in it. So I thought stuff it the fan viscous was $30, dropped the thermo and pulled the viscous out of the D2 which is in great nick and went on home. Fitted the coupling to my fan, pulled the thermo out and put the viscous back in. Right now I just can't be bothered with the thermo. The viscous has sooo much draw in comparison to the thermo it can't be beaten. And compare to my old viscous it kicks ass no wonder I thought a thermo could beat it. I havnt completely given up on the thermo but I think installing less restrictive auxiliary fan is a better idea and leave the viscous.
Ive also found the time to do a compression test the numbers aren't the worst but could be better. Now I done the test sorta warm I had it running for a while but it wasn't enough. I also done the test with the fuel pump fuse out. Then afterward read RAVE on how it's recommended doh..... so it's more a dry lukewarm test....on a low comp engine.
Looking at the engine starting closest to driver. 125 120 125 130 then closest to passenger 130 120 110 125.
The 110 is the only one I'm worried about but I really need to retest properly. So looks like I haven't completely killed it when it got hot, it still drives really well and hasn't warmed up at all or smell with the new fan. I need new rocker gaskets so it's worth opening it up and having a look see at the valve springs...eventually. But overall fairly happy things could have been worse. Also if any wants a D2 fan only it's up for grabs I'll post in proper section.
Cheers Jim

[rangieman]

Good to hear [thumbsupbig]
So you haven`t re invented the wheel after all that[tonguewink]

[DAMINK]

125 120 125 130 then closest to passenger 130 120 110 125.
The 110 is the only one I'm worried about but I really need to retest properly.

Yea #3 does not look great. Does not look like your head gasket is gone though.

I would expect to see 3 meeting 5 and dropping both of them readings if the head was gone there. 5 seen just fine.

Could it be just that pot leaking into your water? Yea possible but lets hope not.

Seems you may have dodged a bullet here mate.

Be very paranoid though. I had my old girls last engine give me warnings before it went poop.

They say your allowed 10% variation between pots(highest to lowest). Your outside that obviously so we have something wrong.

Hopefully just old worn parts rather than head gone.... Not sure which is better actually now i think of it.

Put some oil down #3 and test it again. See if that brings back the missing compression.

[LRJim]

Yea #3 does not look great. Does not look like your head gasket is gone though.

I would expect to see 3 meeting 5 and dropping both of them readings if the head was gone there. 5 seen just fine.

Could it be just that pot leaking into your water? Yea possible but lets hope not.

Seems you may have dodged a bullet here mate.

Be very paranoid though. I had my old girls last engine give me warnings before it went poop.

They say your allowed 10% variation between pots(highest to lowest). Your outside that obviously so we have something wrong.

Hopefully just old worn parts rather than head gone.... Not sure which is better actually now i think of it.

Put some oil down #3 and test it again. See if that brings back the missing compression.Yes it seems I'm pretty lucky and caught it time. For all I know it's been like that since I've owned it. All the readings are holding pressure and not dropping, I done the test myself and checked the gauge a few times before moving to the next cyl. I really need to do the test wet and at proper temp with the throttle open to get the correct results, but at least it's a decent indicator the head survived.
It's not loosing coolant or burning oil so that's always a good thing. But it's definitely out of the 10% ratio. When I redo the test proper hopfully it evens out.
Cheers Jim

[LRJim]

Alright bringing this back, still no overheating which is great.
So I just thought I'd check my A.C fans, they don't come on when I flick the A.C on the cars at operating temp sitting idle.
Do they kick in at a certain temperature?
I checked the fuse all good it's the same as the compressor.
They could have gotten unplugged but I thought I'd ask before I go seaching for nothing
Cheers Jim

[DAMINK]

Just went out to check mine Jim.
Ya wont believe it mate, THE ****ER WONT START lol!! (spark AGAIN i think)

Gotta love the discos man, they keep ya thinkin.

[LRJim]

Just went out to check mine Jim.
Ya wont believe it mate, THE ****ER WONT START lol!! (spark AGAIN i think)

Gotta love the discos man, they keep ya thinkin.Ohh you are joking right?!?! Poor bastard it's a never ending cycle! As long as they die in the driveway it's all good, in the bush or in the Burnley tunnel is death!

[DAMINK]

Ohh you are joking right?!?! Poor bastard it's a never ending cycle! As long as they die in the driveway it's all good, in the bush or in the Burnley tunnel is death!

lol exactly.

Got it going. Either that button at the back of the water bottle or the amp connection. Gave them a tickle and it started.
Aircon turned on and fans were spinning from cold start. I assume they run constant when aircon is on.

[LRJim]

lol exactly.

Got it going. Either that button at the back of the water bottle or the amp connection. Gave them a tickle and it started.
Aircon turned on and fans were spinning from cold start. I assume they run constant when aircon is on.Hahaha just gotta touch her in the right spot!
Alright thanks for checking that out for me I'll have to get it running before I start using my air con. Maybe I can put my big thermos in front hahaha
Cheers

[AK83]

.....
Aircon turned on and fans were spinning from cold start. I assume they run constant when aircon is on.

Zactly!
They're always on with A/C on.

They also come on, if the A/C is off) when the coolant temp hit's a certain temp level .. can't remember exactly but over 100°C from memory.

From what I've read, the actual fans are pretty much indestructible, so look at wiring first.

There's a condenser fan relay located in the driver's kick panel too.
RAVE page's ETM 5 page 1 in the electrical trouble shooting section.

Could be a little bits confusing here too:
I think the Tdi is set up a bit differently to the V8.

Tdi has a couple of switches in the cooling system for the condenser fans, and a realy to operate them.
I reckon there may be a typo somewhere too in there, on one page it's listed as K109, but the same relay is then marked as K190 too in another section further down.

But the V8 seems to have a Fan Control Module(component Z118) still down at the kick panel.
See page 38 of the Z5 section of the ETM.

[PhilipA]

If it is an older Disco which it looks like from your photo tiny as it is, then the aircon fans should be on all the time the A/c compressor is on.

If is it a V belt one, there should be a switch on the side of the thermostat which switches the fans on at 105C. Dunno about multi belt ones but probably the same. Mine only ever came on once climbing Mt Pinnibar in low range.
That is if it is the same as an RRC 3.9.

The best way to start troubleshooting is to run a 12v wire from the battery straight to the fans. You should find a connector near the radiator. If the fans start on 12V then they are Ok , then run backwards from there.

Regards Philip A

[LRJim]

Cheers Phil and AKD yes it's a D1 but after the facelift it's a 96 or 97. I'll definitely start by running a direct wire from the battery see if I can get them spinning. Then work my way back from there. I'll probably put an override switch in for towing while I'm at it. I'm not sure about the V belt I have a feeling it runs off the serpentine. Or do you mean V belt serpentine which it's definitely not. It's still a bit smelly but I think I've spilled some coolant last night.
Lol yes my photos tiny it's just the avatar I havnt got on my computer to muck about with it all.
Cheers Jim

[PhilipA]

Yes it will be a serpentine.

LR made lots of changes over the life of the 3.9. in 89-91 they had vbelts, in 92 they had a combination with a serpentine type running the alternator but Vs elsewhere and I think 93 went to serpentine.

I have a big gap in knowledge of this between 91 and 2002 TD5.LOL

BUT it will still probably have an overtemperature switch somewhere which you can bridge with a manual switch.

Remember to earth the fan when testing if you separate a connector.
Regards Philip A

[bee utey]

Yes it will be a serpentine.

LR made lots of changes over the life of the 3.9. in 89-91 they had vbelts, in 92 they had a combination with a serpentine type running the alternator but Vs elsewhere and I think 93 went to serpentine.

I have a big gap in knowledge of this between 91 and 2002 TD5.LOL

BUT it will still probably have an overtemperature switch somewhere which you can bridge with a manual switch.

Remember to earth the fan when testing if you separate a connector.
Regards Philip A

I believe the over temp switch is still on the thermostat housing just like on the earlier models. I've come across quite a few stuffed ones, both permanently on and off. Bridging the wires is the first step for diagnosis.

[Old Farang]

I believe the over temp switch is still on the thermostat housing just like on the earlier models. I've come across quite a few stuffed ones, both permanently on and off. Bridging the wires is the first step for diagnosis.
P/N PRC3505, has to 2 x 6mm terminals.

PRC3505 - Switch Temp Sensor Yellow 90/110 2.5DT and V8. Discovery 300TDI and V8. Range Rover Classic V8 (https://www.johncraddockltd.co.uk/range-rover/range-rover-classic/parts/engine/prc3505-switch-temp-sensor-yellow-90110-2-5dt-and-v8-discovery-300tdi-and-v8-range-rover-classic-v8.html)

[LRJim]

Done some simple poking around with a test light. Turned A.c on, probed the wires at the condenser fans and the light came on but no fans. My best guess is the fans are cactus, powers getting to them. Anyone ever upgraded the fans before?

[PhilipA]

Done some simple poking around with a test light. Turned A.c on, probed the wires at the condenser fans and the light came on but no fans. My best guess is the fans are cactus, powers getting to them. Anyone ever upgraded the fans before?
Hmm, I think it could be possible for a test light to have 12volts but no current.
I would still run a hot wire from the battery to the fans, rather than through the system.
That way you are sure about whether they work or not.

I have replaced fans often. I usually use just Supercheap or Ebay or whatever fans but order ones with a similar wattage or current draw. I think they are 12 amp but not sure. Try to get waterproof ones. make up mounts to suit.
Sometimes you can get a larger fan to fit by making mounts and diddling about a bit.

Regards Philip A

[bee utey]

Replaced a few dead RRC fans in my time. Fit whatever fits.

[Rick1970]

Condensor fans on my old rrc had a ford sticker on them, not sure what ford they came from tho.

[LRJim]

Condenser fans are defiantly cactus, tried running power to them and nothing. Ran multimeter over the wires, read 12v on and 0v off. Don't have any fans laying around that will fit bummer. Would using the a.c. without the fans kill the condenser? I'll get some new ones later in the week but with the baby in the car i may need the a.c. till then
Cheers Jim

[bee utey]

Condenser fans are defiantly cactus, tried running power to them and nothing. Ran multimeter over the wires, read 12v on and 0v off. Don't have any fans laying around that will fit bummer. Would using the a.c. without the fans kill the condenser? I'll get some new ones later in the week but with the baby in the car i may need the a.c. till then
Cheers Jim

The air cond may trip out at its high pressure switch setting or even burst a hose if it's too unhappy, although that's not likely as you shouldn't be into the 40 degree days yet. The main engine fan should assist air flow across the condenser unless you're idling for a long time.

[LRJim]

The air cond may trip out at its high pressure switch setting or even burst a hose if it's too unhappy, although that's not likely as you shouldn't be into the 40 degree days yet. The main engine fan should assist air flow across the condenser unless you're idling for a long time.Not gonna be idling too much mainly freeway drive. It's only in the mid 20s but warm with the windows closed up. If it was just me I'd have them down but it's annoying with the baby in the back. My other cars that have a viscous don't have condenser fans. Or the commo just has a thermo for both. I'm sure it will be alright in this temperature.
Cheers Jim