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

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

Originally Posted by 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

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.

Originally Posted by PhilipA

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.

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.

Originally Posted by DAMINK

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

Made by Denso, not some useless UK Co.!!

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.

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


Rover V8 engine - Wikipedia

Discovery radiators have narrow tubes which doesn't help.

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 andteaspoon 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

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