1HD-FT Cooling question

[Gary Stockton]

Hi all

Anyone able to tell me the normal temp. range on the 24v motor?? Driving down through France it was 37 degrees outside and the temp gauge was steady on 85 which is normal.

But then I hit a long grinding hill and got stuck behind loads of traffic nearvLyon and the EGT went up to 670 and the water temp to 92.

Got it all back down I to the green but a just wondering what 'normal' is on the 80's...

 

[Charlie]

I would say that's normal (compared to my truck), but just to be sure give the radiator a good wash.......

 

[Gary Stockton]

Will do - should have mentioned the cooling system was flushed and refilled with Toyota red coolant (12litres of it) about a month ago. Gave the rad a good spray through then but will do it again here.

I did notice a 100% correlation between the EGT and water temp though, so an intercooler has moved up the 'I want' list and because SWMBO was witness to all this she is in 100% agreement ...

 

[Chris]

You got anything blocking airflow over the rad at all Gary? Big spotlights and so on all take their toll. The AC condenser is in front as well so the air has quite a journey to get to the rad. Viscous fan running OK? Doesn't alter the answer in regard to what the temp range is but worth looking why it got up there to start with. I doubt it's blocked inside but worth looking through it. They get quite clogged over time and the middle might be clear but the edges can be solid.

 

[Shayne]

1HD-FT 76 degree stat just thought a part number might save you some time

 

[Towpack]

High EGT's for more than a few minutes at a time will certainly make the coolant temp climb rapidly. You don't say where your EGT thermocouple is mounted but if it's downstream of the turbo then a sustained 670 c (1238 F) is getting dangerously high IMO. Towing uphill on the motorway in top I can easily hit 1200F+ (pre-turbo) so I always change down a gear. The OE coolant temp gauge hardly moves from halfway on mine but they're not the most responsive of gauges so no idea really what the actual coolant temp is. When I pull off the motorway after towing I can hear the roar of the viscous fan so it's obvious the temp is up there. EGT's are directly related to engine load so can't see how being in heavy traffic would increase them. Slow moving traffic usually helps decrease EGT's in my experience. Did you fit a new stat after the flush? Could be a duff one or wrong rating maybe.

 

[Dave]

If its auto, that will be dumping in a lot of extra heat in traffic and up hills unlocked.

 

[Gary Stockton]

So no obstructions. The sensor is pre turbo. I know exactly what I did wrong - I was pootling along using the cruise control at about 70-ish and didn't twig really until the alarm sounded so the engine was labouring (doh). Serves me right - too many hours motorway driving. I suspect the thermostat is fine but will swap it out with a new one when I get home just to be sure.

I'll also give the radiator and condenser a good soaking clean and check the fan operation.

Many thanks folks.

 

[Dave2000]

Worth noting a couple of things here.

First the stock temperature gauge is 'dumbed down', sits more or less mid way until there is some serious heat build up in the engine, there is a mod for the gauge to make it react more closely to the actual engine temperature, I have done this mod and can confirm it's worth.

Next, the 80 is unusual in that the thermostat is in the bottom hose and not the normal top as per most other vehicles, this means the gauge reading can climb (along with engine temp) quite awhile before the thermostat actually starts to open and not in unison as is the norm.

And the usual suspects, faulty VC on the fan, padding around radiator missing, spotlights, blocked A/C condenser and or radiator and/or between the two, auto dumping heat, and so forth, and something I picked up by chance. The hose to the expansion tank, as it ages it softens, we know that as the engine heats up it forces water into the expansion tank along that hose and no problem except, as the engine cools it wants to draw the coolant back into the radiator, I have found on some vehicles air gets pulled in through the connections between the rad/expansion tank connections, this allows a large air bubble to accumulate at the top of the radiator, this lack of capacity (around a litre) allows the engine to run hotter.

FWIW, I have taken off the VC mechanical fan and fitted an electric version, at the moment the install is under test but the A/C performance at idle easily outstrips the VC fan, all info in my sig.

regards

Dave

 

[Chris]

I like the idea of an electric fan I have to say.

 

[chapel gate]

I would say the easiest and cheapest way to knock your egt down would be to up your boost if you havnt all ready.

 

[t1pper]

Hi,
My 2P's worth it's probably the rad.

The original cooling system should work well without modification additionally a known engine that does not generally over heat or give any cooling related problems, leads me to believe an inefficient rad is to blame.

Even a small build up of crud inside the rad and outside dirt/air flow restrictions will mean it is not able to dispel the heat efficiently, you will not realise that the radiator is slowly getting less efficient until one day the ambient temperature is hotter than normal and you are working the engine a bit harder.

I always think that rads have to be really clean to work effectively, my best example is, you can pick up something very hot by using a piece of rag just a few millimeters thick without getting burnt, take away the rag and the heat will transfer instantly.

I have found flushes are not that great at cleaning gunked up rad internals, I would strongly suggest you look closely at the rad especially if you do not know when it was last changed plus leave doing any mods or looking for further problems in the system untill the rad condition is confirmed.

 

[Dave2000]

I like the idea of an electric fan I have to say.

Check out my LC 80 thread on MUD, link in sig, if you have read through it also mentions the temperature gauge mod.

regards

Dave

 

[frank rabbets]

A drawback with an electric fan is that it may not be as reliable as the viscous couple one fitted as standard.

Unlike a petrol engine adding more fuel to a diesel will increase the combustion chamber temperature which may well not be seen on the standard temperature gauge.

The egr valves on the 80 are there not just for pollution control but also to prevent excessive combustion chamber temperatures under certain circumstances monitored by the ecu.

 

[IRLGW]

have you checked that the heater matrix isn't airlocked and restricting the flow. When you mention the recent coolant change I remember a similar problem only it was winter and the cab wouldnt heat up. If it had been summer it would have gone un-noticed. I disconnected the heating hose under the windscreen and shoived the end of the garden hose on it to force water back into the system. Even driving in the alps for long periods I never had any temp issues so maybe worth checking if you think you are running hot.

 

[chapel gate]

A drawback with an electric fan is that it may not be as reliable as the viscous couple one fitted as standard.

Unlike a petrol engine adding more fuel to a diesel will increase the combustion chamber temperature which may well not be seen on the standard temperature gauge.

The egr valves on the 80 are there not just for pollution control but also to prevent excessive combustion chamber temperatures under certain circumstances monitored by the ecu.

How do they prevent excessive temps frank?

 

[frank rabbets]

Presumably by not deviating from the design and settings of the original car.

 

[Dave2000]

Agree Frank, hence the way 'over spec' of my install, check out my work in my sig link. Done a few installs years ago which worked but were at the limit given we only had dynamo's (stop laughing at the back there!) The MK1 Granada, 3,000 Capri, V12 XJ Coupe. And even my last 4x4 LD Discovery all had electric fans. We are presently observing a severe weather warning (red 38 C) in the area I live in, pretty much unheard during June, July and August could hit 45+...GULP! At least I will have the opportunity to test the install under extreme conditions.

IRLGW has a very good point. Many are familiar with the cable operated heater valve but, many are NOT aware that the heater valve does NOT move in direct response to the slider at the heater control. The ignition must be on, then the heater slider moved to HOT, this allows a servo/motor to operate the cable, and then the ignition switched OFF, the valve will remain open, now you can fill the radiator slowly.

regards

Dave

 

[chapel gate]

i see egt and a cooling problem as two different things. the egt the op was getting are similar to mine foot down on the motorway, on a incline fully loaded. either put more air in or less fuel, both will bring egt temps down.

i limped home from cornwall once with a caravan on, literally a needles width below red all the way.there was no significant increase in egt.

i would guess maybe high egt will increase water temp, high water temp wont increase egt.

 

[Bat21]

Check out my LC 80 thread on MUD, link in sig, if you have read through it also mentions the temperature gauge mod.

Any idea which post in the 13 pages your temp gauge mod is in Dave?