Cooling issues 1HDT

[roaminglost]

Chasing these hot temps! Nothing seems to be working. So far…

Truck runs / idles around town at 90 C
But anything that makes it work. Going up a slight grade at 60 mph. Temps got to 105-110 C. Temp outside was 90 F.

Replaced the radiator, hoses, cap, thermostat, a modded light blue fan clutch from redline cruisers and new fan.

Someone always says, take the stuff off the front. Yeah I get it. But seems like people run similar setups with no complaints?

Next up I ordered a water pump and belts to swap all that out. But my next guess is head gasket.

 

[roaminglost]

I bought an infrared temp gun; my gauge says 90 C at idle. The Gun is saying 76.3 C off the top radiator hose. Even tho the temp is wrong, still seems high?

(my temp reading comes from the secondary tap on the top radiator hose.)

 

[Squash]

If an automatic drop into 3rd on steep hills and maintain rpm, you do not want the tranny hunting for gears and increasingheat.. I use 3000rpm as my baseline, truck maintains speed or increases. You want the engine turning, water pump pumping and the fan blowing. Never let the engine lug or lose rpm because you are just making heat.
Also don't stop once you've crested a hill to measure heat because now you have stopped the important cooling process.
This is why our gauges barely move until the pass 100C.

 

[mudgudgeon]

my gauge says 90 C at idle. The Gun is saying 76.3 C off the top radiator hose.

Why the huge discrepancy?

I'd look at the probe and gauge first, check that you are getting accurate temperature reading.

Do a temporary hook up of gauge on the bench and put the price in a tin of boiling water.
If you have another thermometer even better.
When water gets to a rolling boil, you should see 100⁰c

Verify your temerature reading before loosing sleep over head gasket

From memory, 1hd-t normal operating temperature is between 86⁰c ( thermostat starts to open) and 95⁰c ( thermostat fully open).

Also, is the light blue fan correct to your vehicle?
There's different length hubs for different engines. The different length is to position the fan correctly in the shroud.
Looks a bit like your fan is sitting outside the shroud more than normal, but i'm not certain.

105-110⁰c is ok if that's a peak when worked hard. With the correct coolant mix, and correct pressure rated radiator cap, coolant shouldn't boil until around 120⁰c
90⁰f ambient temp shouldn't be a problem. The only time I ever saw my temperature gauge move on my hdj80 was on a 45⁰c+ day (115ish⁰f) me angry, and driving my tuned up truck like I'd stolen it up a Mountain pass.
Had to stop and cool off metaphorically, physically, and mechanically

I agree with @Squash above, driving habits can affect the amount of combustion heat these produce.
Your engine is much happier at 3000rpm than it is struggling at 2000rpm. Just maybe not 4000+rpm on a 115⁰f day

 

[TheBussman]

Up to 110 is fine, if your not going over that i wouldn't be worried. if your not loosing coolant your head-gasket is probably OK. from the factory the cyl head temp sensor for the gauge is in the middle of the head not the coolant outlet. That's usually where the AC cutoff switch goes. I'm not sure what location would give a hotter reading. The outlet has all that coolant that just came from the turbo right in front of it I think it could be a little hotter then the middle of the head. do you still have the original temp sensor? Just for a test you could go on a test drive with a ohm meter temporally connected and see what reading you get and compare it to your current gauge.

 

[mudgudgeon]

Never mind. Had what I posted backwards

 

[roaminglost]

I was playing around with fuel, dropped it down, and I seemed to have gotten 10 degrees cooler on the loop I was doing.
Going from hitting 105 C on the gauge to 95 C

3rd gear 45 mph = 95 C (my IR gun reads 10-12 degrees less off the radiator hose) so roughly 78-80 C

I also took my front pods off; they didn't change any cooling. The new fan pulls pretty strong.

 

[CaptBeardilocks]

Oil cooler on the side of the block is known on these engine to occasionally get blocked up and contribute to over-heating issues.. Especially if it was ever run in the past on either straight water or mixed red/green coolant. It's a bit of a PITA to get off, but so is the head

It wouldn't hurt to run compression and possibly leak-down. I like to run compression to have a baseline for when things get weird later.

Are you monitoring EGTs as well? That would be another bit of helpful data. If EGTs are normal but coolant is high that's one thing. If EGTs are way too high, you're looking at over-fueling or something else that could contribute to higher coolant temps.