300 tdi engine temps

[460cixy]

Having a few temp issues with the disco on these last couple of days its been 38/39c here and the old disco is not loveing life radiator was rodded out about 4 months ago in preparation for summer new fan hub and all the bugs blown out of the a/c condenser and trans cooler thermo fans all checked and functioning.

If the ambient temp is not over about 35 it will run at around 80-85c but if worked hard climb up to 88-90c for short periods then back down to normal with the a/c on so as a precaution I fitted a 80c thermostat in the hope it might help it run around the 80c mark

In this hotter weather it slowly climbs to 90c+ just at cruise with the a/c on turn the a/c off and it really struggles to drop the temp back down its like there's just no reserve capacity in the cooling system at all. Actually its hopless to be honest

The spot lights will come off this arvo not that there huge and was thinking of removeing the grill temporarily to see if it improves things any other ideas?

[jboot51]

Mine sits on 95 with a max of 99 on the hwy.
Around the back streets it will be 92.
The viscous fan locks up noticeably at 95.
Vdo temp gauge is installed

[jboot51]

And that is with ac on or off.
Also ambiant temps make little difference.

[460cixy]

Wow ok that's pretty bloody hot seing the standard thermostat is 88c I recon its too close to the limit for comfort the defender got recored last year and runs much cooler but has not got all the other junk infront of the radiator

[jboot51]

(In our group) There are 3 of us that kick around in 300 tdi defenders and all the temps are similar.
All 3 are running the plastic/ali rads.

[460cixy]

Mine are both original copper just ones got a new core

[Judo]

I get coolant temp over a 100 very regularly in summer. Head temp up to and a fraction over 100 sometimes. (My record is 101 or 102, can't remember). I find coolant can be up to 5 degrees warmer than head sensor when driving hard. Top end of the scale is head temp 100 and coolant at 105.

How do I do it? Slightly over-sized tyres, roof rack, bull bar, winch, fridge, passenger and AC on. Piece of cake. :) I really want to try the "tropical mod", but it's just not on the priority list...

[460cixy]

Tropical mod? Is that blocking off the 5/8 hole in the divider mines been done

[Brett1066]

I don't normally get above 90 deg, coolant is always a little lower than the head temp, even last week when it was 43 degrees here. Haven't done a long drive for a while, but around town and stuck in traffic on hot days my temp won't go above 90.
Mind you, I pulled out the air con condenser recently (seeing as I had previously removed the air con unit from the cab as it hadn't worked in years) when I fitted a new viscous fan, and am getting much better airflow over my radiator than I was previously. Even then though, never saw the temp get above about 92-93.
Assuming you have checked all the obvious things - air lock, blocked hose(s), water pump working properly etc...

[460cixy]

Yeah every things tip top even a new copper heater core to replace the old leaky one only thing I can't be sure of is the state of the water pump impeller but you give it a rev with the cap off and there's plenty of flow through the bleed hoses so I'm confident its ok. Just brought a set of ford el/ef falcon fans off a bloke wrecking one up the street but seriously at 100 kph you would think there would be plenty enough air flow not to need to resort to stuff like that

[Judo]

Tropical mod? Is that blocking off the 5/8 hole in the divider mines been done
Yes. Maybe that's why you're only getting to 90? I'm hitting 10*C more than you!

[roverrescue]

I have played with my 130 radiator in all ways
It currently is running as 4 pass (ie water crosses from left tank back and forth four times before exiting)
No difference still can get it up to 115 up the byerstown range in midday summer
(oh and this is of course on an engine with no head troubles etc etc sorted that )
In honesty the trouble is the aero design of the fender. Up to about 90km/h you get good airflow across the radiator.
Over that speed and the air stalls

When it is hot (as in road temps over 35 and high humidity) the fender is at its cooling limits

I take solace in the fact that glycol+water at 15psi wont "boil" until 130 degrees so despite perhaps a little pump cavitation as long as temps stabilise after hills I just keep plodding.

But if your head/ gasket or cooling hoses are suspect then the extra pressure wont help!!

Talk of whacking holes in the side guards to better airflow has been made

Honestly might be better just to disconnect the temperature guage.
The factory gauge is normalised between 80-110 ie it wont start moving till your up over 110

maybe some logic in that - don't sweat that which you cant change!!!

S

[Judo]

I have played with my 130 radiator in all ways
It currently is running as 4 pass (ie water crosses from left tank back and forth four times before exiting)
No difference still can get it up to 115 up the byerstown range in midday summer
(oh and this is of course on an engine with no head troubles etc etc sorted that )
In honesty the trouble is the aero design of the fender. Up to about 90km/h you get good airflow across the radiator.
Over that speed and the air stalls

When it is hot (as in road temps over 35 and high humidity) the fender is at its cooling limits

I take solace in the fact that glycol+water at 15psi wont "boil" until 130 degrees so despite perhaps a little pump cavitation as long as temps stabilise after hills I just keep plodding.

But if your head/ gasket or cooling hoses are suspect then the extra pressure wont help!!

Talk of whacking holes in the side guards to better airflow has been made

Honestly might be better just to disconnect the temperature guage.
The factory gauge is normalised between 80-110 ie it wont start moving till your up over 110

maybe some logic in that - don't sweat that which you cant change!!!

S
I've wondered how close I'm getting to the limit, but you can hit 115 coolant temp and no apparent issues to speak of? From all the reading on here, it seems to me if the factory gauge moves, you will end up with head gasket issues. If the factory gauge is normalised to 110, then I can't see 110 being safe. Thoughts?

[460cixy]

Would a disco have the same air stalling issues? I heard the p76 had a simlar issues at speed when the shape of the car at certain speeds created some sort of positive presure area and would then get hot

[roverrescue]

-generally the factory gauge moves BECAUSE you have a head gasket problem
-It has been years since I tested factory against VDO but from memory it was 110 before the factory went up
-If I hit 110 going up a range with stupid heat and humidity (good examples are Byerstown near Palmer or Bamboo range north of Laura) the temp will settle back to mid 90s once power comes off or get to top of the hill.

Im not advocating pushing an alloy head that hard often but I guess I have not had super problems.

Also having said that some people are scared of 300 head gaskets. This plays into the fears of temps? Last change out I did of a 300 head started at 830am and was drinking beer by 1100am on a Saturday morning... Id take a head gasket change over doing the swivel hubs or control arm bushes for example?

Maybe Im too blas? but if the temps start to fall as soon as the noise comes off and then stay down until the next big engine load well then Im okay with that?

If you drove your 300 powered defender at 85km/h or less everywhere I doubt you would ever get much over 90... I think it was Rick (rick130) who did some aero testing and found the air stall speed was about 90-95km/h - once you hit that the only cooling you are getting is via the viscous fan drawing air over the rad.

s

[460cixy]

No issue doing heads gaskets just think they run a bit hot is all and if I can improve it for not much money I think it makes sence not that I can see any sure fire way of geting them to run cooler

[roverrescue]

From what I have seen the only way to get them running cooler will be an alternative to factory rad however space is not your friend or whacking some big holes down your guards so that the stalling air can flow when at highway speeds

Other than that call it a design feature from colder climates!

[Judo]

-generally the factory gauge moves BECAUSE you have a head gasket problem
-It has been years since I tested factory against VDO but from memory it was 110 before the factory went up
-If I hit 110 going up a range with stupid heat and humidity (good examples are Byerstown near Palmer or Bamboo range north of Laura) the temp will settle back to mid 90s once power comes off or get to top of the hill.

Im not advocating pushing an alloy head that hard often but I guess I have not had super problems.

Also having said that some people are scared of 300 head gaskets. This plays into the fears of temps? Last change out I did of a 300 head started at 830am and was drinking beer by 1100am on a Saturday morning... Id take a head gasket change over doing the swivel hubs or control arm bushes for example?

Maybe Im too blas? but if the temps start to fall as soon as the noise comes off and then stay down until the next big engine load well then Im okay with that?

If you drove your 300 powered defender at 85km/h or less everywhere I doubt you would ever get much over 90... I think it was Rick (rick130) who did some aero testing and found the air stall speed was about 90-95km/h - once you hit that the only cooling you are getting is via the viscous fan drawing air over the rad.

s
Interesting first point. You could be right - or at least some of the cases happen that way around. I know my case was definitely in order of overheating, then head gasket soon after.

I hear you on the temp dropping back after coming off the power. My VDO gauge hits 105*C, but as soon as I'm over the hill the needle drops at rapid speed.

BTW, mine is a Disco, so it may not have the same airflow problems?

[460cixy]

See mines mesureing head temp not water and that may be why its taking so long to come back down on the gauge

[Judo]

Yeah, my head temp sensor is much slower to move, both up and down.

Seriously though, from your first post, if you're only getting 90+ then you have it great! About 10*C spare over mine. Load it up. :)

I agree with roverrescue if you really want to "fix it" though - there is no substitute for a better radiator. The only options as I see it are a drop-in replacement that claims to be more efficient (I'm not sure how good these are really) or a wider replacement and new intercooler mounted in front (custom work).

[460cixy]

You might have a point there maybe I shouldn't be such so soft on the old girl but it has got 400,000 on it

[Judo]

Mine has less than half that, so I better not make any guarantees. ;)

[Brett1066]

If you drove your 300 powered defender at 85km/h or less everywhere I doubt you would ever get much over 90... I think it was Rick (rick130) who did some aero testing and found the air stall speed was about 90-95km/h - once you hit that the only cooling you are getting is via the viscous fan drawing air over the rad.

s

Explains why my temp never gets over 90 - the old girl very rarely goes over 90km/h.

[rover-56]

Don't really understand all this talk of overheating, my 95 Defender with 88deg thermostat sits at 80 most of the time and climbs to 88 on hills on hot days ( like yesterday, 39deg) with the pedal pinned. Comes down pretty quick after.

All stock, I have a thermocouple clamped to the back of the thermostat housing. Had it in the gauge sensor location for a while, no different.

Yes I checked the indicator against a mercury thermometer.

If you measure at that plug between cyl. 2 & 3 you will get a fright - mine reads 110 there on normal days on hills.

I suppose the Disco is different with the a/c condenser in front, fuelling wound up will push things a bit too.

LR supposedly designed for hot climates?

Terry

[460cixy]

Yeah it seems there all over the shop the defender runs cool and is fuelled up too. The disco is standard except the tyres but there only 245/75/16 so not a huge differance over standard

[rover-56]

I think the rad. core may be the key to it. They can look clean but be part blocked.
Rodding doesn't cut it, you still have a layer of crud stuck to the tube surfaces.
Terry

[roverrescue]

I find this funny
"If you measure at that plug between cyl. 2 & 3 you will get a fright - mine reads 110 there on normal days on hills."

So head water jacket temps of 110 are less valid than whacking a thermocouple in the airflow at the thermostat housing?

All my temps are measured via a VDO probe in factory location head water jacket just before water enters the thermo housing

when your temp doesnt rise going up hills in 39 degrees is that after driving at 110 for a few hours prior to the hill and punting up the hill flat to the boards? 90% humidity likely doesn't help either.
Issues being raised are a function of poor cooling capacity when at highway speeds and airflow over the radiator is diminished..
.Temps being measured are actual water temps in the head galleries.

Cest la vie

I say defenders have limited cooling capacity you disagree

s

[rover-56]

I say defenders have limited cooling capacity you disagree

s

No, I just don't know.
There are all sorts of variables between vehicles, I just know that my temp sat on ~80 on the flat for a couple of k's then flooring it on a 5 min hill in 4th
takes the temp up to 88, no higher. Repeated several times in 140km, sea level to 900m in 2 hrs at 39deg.
The sensor is tucked behind the thermo housing out of the airflow. It is metal temp though. I am just guessing that my rad is clean.
Terry

[rick130]

Mine sits on 95 with a max of 99 on the hwy.
Around the back streets it will be 92.
The viscous fan locks up noticeably at 95.
Vdo temp gauge is installed

Ditto, and I have a new (six month old) HD Redback core and the hole in the divider blocked.

[edit] coolant temp via a VDO mechanical gauge with the bulb in the stock location.

[rick130]

... I think it was Rick (rick130) who did some aero testing and found the air stall speed was about 90-95km/h - once you hit that the only cooling you are getting is via the viscous fan drawing air over the rad.

s

Which is why this works on a Deefer. http://www.aulro.com/afvb/90-110-130-defender-county/144905-defender-engine-bay-heat-lh-guard-vent.html

[rick130]

Honestly might be better just to disconnect the temperature guage.
The factory gauge is normalised between 80-110 ie it wont start moving till your up over 110

maybe some logic in that - don't sweat that which you cant change!!!

S

Yep, ignorance is bliss !

I thought the cooling system was amazing with the stock electric gauge on 38* days with the rad blocked with grass seeds.

It only moved when crossing the range where I used to live. :D (I actually typed 'here'. took me a minute to realise the mistake.


Matt, check the switch settings on the thermo fan switch for the Disco, IIRC they are up around 108-110*.
I remember being a little surprised.

[460cixy]

I've never had them come on by them selves only with the a/c as there meant to i should check the switch is functioning as it should This afternoon in the cool a/c on humid as hell just before the rain flat out and it never cracked 78c ambient about 32c

[Tins]

Hmm... Mine rarely strays above 82/3. Long runs on the freeway at 110k will see it climb to around 90, probably needs a rad clean. Last week though, in Melb on the 41 degree day, I was out and about. Went to my mum's house and parked it for about half an hour. When I came out the temp alarm went off as soon as I turned the key ( set at 111 when I got it, left it that way cos I didn't know any better ). Temp came down to around 100 about 1 min after I started it, but claimed again to maybe 109 when I drove. Factory gauge started going up. No thermo fan activity. I turned on the A/C switch ( no belt fitted, so no actual A/C. Did I mention it was 41 degrees? :firedevil: )

and the temp started coming down. Idled it down at home for a few minutes and it was back to low 80s. It showed no sign of boiling, and it seems fine now, but I've been worried. Having read this thread I'm not worrying as much, but now I'm wondering if my thermostat is too cool.:mad: the only time my TD5 got hot was when it did a head gasket ( head shuffle, 240,000 ks ).

[loanrangie]

I would start to worry, i had very similar symptons on the same 41 degree day except mine was pushing coolant out even the next day when it was cold.
Spent the weekend pulling head and replacing gasket after checking head was good and straight.

[Tins]

No sign of that so far, thankfully, as I hurt myself before Christmas and am still impaired, so pulling the head off doesn't appeal. I couldn't even do the timing belt as I've been promising him ( all my cars are she/her, but my son christened this one Dave. What do you do? ). But thanks, I'll be watching. Maybe when I'm fit and the D2 decides to come home from Adrian's place I'll pull the head anyway, unless he forces the issue.

[460cixy]

Pulled the spot lights off and it seems to have simmered down but it has not been real hot

[Tins]

I would start to worry, i had very similar symptons on the same 41 degree day except mine was pushing coolant out even the next day when it was cold.
Spent the weekend pulling head and replacing gasket after checking head was good and straight.

I expect you're right of course. The wretched car exhibits no outward sign of anything being amiss; no coolant loss, no boiling, no foaming, no pressurization. The temp climbs from cold at the usual speed, but it doesn't stop at 82 like it always has, it keeps going up. Time for the head to come off.

[steane]

Mine sits on 95 with a max of 99 on the hwy.
Around the back streets it will be 92.
The viscous fan locks up noticeably at 95.
Vdo temp gauge is installed

As a comparison, mine sits on 90/91 most of the time, 92/93 on the highway if it's a warmer day or an uphill run. Fan locks up at 98 and the only time I've seen 98 recently was when towing an 1800kg boat up a bloody steep hill at highway speed or overtaking when towing same boat and forgetting to watch the EGT for a moment.

EGT goes up and coolant temp follows pretty quickly.

Prior to having the rad rodded a few years back and getting the tune right, It would happily go over 110c on mild inclines not towing. Viscous fan was always very quick to drop it back to 108 when it did.

VDO temp gauge as well.

[Tins]

I expect you're right of course. The wretched car exhibits no outward sign of anything being amiss; no coolant loss, no boiling, no foaming, no pressurization. The temp climbs from cold at the usual speed, but it doesn't stop at 82 like it always has, it keeps going up. Time for the head to come off.

Actually, perhaps I'd better check the thermostat first.

[loanrangie]

Actually, perhaps I'd better check the thermostat first.

What i will be doing this weekend as well, car was running great after fitting new head gasket, yesterday on way home i heard a bang and the coolant tank had split along the seam and above.
No temp rise and no bubbling, just bang and all over - thinks its new head time.
I found a suspicious looking seal in the tank and not sure where it came from :o.

[Tins]

What i will be doing this weekend as well, car was running great after fitting new head gasket, yesterday on way home i heard a bang and the coolant tank had split along the seam and above.
No temp rise and no bubbling, just bang and all over - thinks its new head time.
I found a suspicious looking seal in the tank and not sure where it came from :o.

Wow. Must have been some pressure in there to do that. Let us know what you find.