Overheated 1HD-T (1 Viewer)

[ScottJacob]

Hello folks, I was driving my 80 series today, exited the highway and then went to go back on to the highway and noticed the temp gauge was just on the edge of the red (Maybe slightly into the red). I pulled over immediately and shut the engine off. The coolant reservoir was overflowing a bit. What are the chances that I damaged the engine and what are the best ways to check if damage has occurred? I religiously watch my temp gauge, so this must not have been heating for long.. but I'm super worried.

 

[SpenserAK]

The gauge is really just a “dummy”... the temperature range in which the needle stays dead-center is actually quite broad. Sadly, it seems it only starts to move toward red when you’re already starting to overheat. There’s an electrical mod that makes it more accurate, but for real-time temp you’ll need a scangauge or equivalent.

It’s not automatically game-over when this happens, but depends on all the factors. Hopefully when you check things out, all you’ll need to do is tend to the cooling system and be on your way.

 

[mudgudgeon]

Yep, if it's hit the red, it's too late.

But, if it only just got to boiling point you're probably ok, provided there's no underlying issue.

Your should be able to run the 1HD-T at full noise for extended duration without having to watch the gauge like a hawk.
The only time I saw my tuned up 1HD-T approach the red was after pushing it hard in the mountains in 40⁰C heat.

The fact you've overheated at all tells you something is wrong.

May be as simple as a bad radiator cap, or bad thermostat, or bad head gasket, or cracked head, or bad smokey tune up by someone who doesn't understand what they are doing.

You might be lucky.

I had a 1HZ with a cracked head. I boiled it, but shut it down after it had been running a max of 15 minutes from start up. It puked all its coolant, puked oil, and siezed when I shut it down.
After it cooled off it turned over ok by hand. I swapped the cracked head out, and the bottom end was okay.

 

[Dusten]

The gauge is really just a “dummy”... the temperature range in which the needle stays dead-center is actually quite broad. Sadly, it seems it only starts to move toward red when you’re already starting to overheat. There’s an electrical mod that makes it more accurate, but for real-time temp you’ll need a scangauge or equivalent.

It’s not automatically game-over when this happens, but depends on all the factors. Hopefully when you check things out, all you’ll need to do is tend to the cooling system and be on your way.

It's a 1hdt, there's no scangauge or equivalent. There's no ECU. He'd need an actual temp gauge.

 

[mudgudgeon]

It's a 1hdt, there's no scangauge or equivalent. There's no ECU. He'd need an actual temp gauge.

There's alternatives such as a Watchdog that takes a temperature reading from the head with no need for ECU.

 

[Dusten]

There's alternatives such as a Watchdog that takes a temperature reading from the head with no need for ECU.

That's still a gauge using all aftermarket parts.

 

[mudgudgeon]

That's still a gauge using all aftermarket parts.

Yes it is.
But works on any vehicle, not reliant on a signal from an ECU, and is independent of the factory sensor

About $100 from memory

 

[Dusten]

Yes it is.
But works on any vehicle, not reliant on a signal from an ECU, and is independent of the factory sensor

About $100 from memory

Which was kind of point.

The 1hdt can't use something like a scan gauge. So you'd need a complete gauge setup.

 

[sunrk]

I've been running Watchdog coolant temp monitors in vehicles for a lot of years. The TM2 is no longer made (it has 7 segment LED number display) but my 80 has had one of those for 10 yrs connected to the 1hz motor.

The main problem with the factory gauge apart from the 'dead band' is that it's not calibrated or accurate in any measurible way. If you want an accurate display of engine temp an aftermarket unit is the only option.

 

[MonsterCruiser]

@ScottJacob If it makes you feel any better my truck got to about the same area on the factory gauge and nothing got damaged on mine. I also check my gauges frequently, and now have an aftermarket temp gauge as well. I had some coolant coming out the overflow, but there was still coolant in the rad as well. In my case, it turned out to be a plugged up old radiator. A new radiator was installed, and I've never had any issues since. That was in 2013. So about 9 years and I've put about 150,000 kms on the truck since then.

 

[ScottJacob]

Thanks a lot for all of the responses folks! Any tips on tests that I should do to ensure that there wasn't engine damage done (compression test, cooling system pressure test, etc.)?

 

[Dusten]

Thanks a lot for all of the responses folks! Any tips on tests that I should do to ensure that there wasn't engine damage done (compression test, cooling system pressure test, etc.)?

Compression test will help determine if there are any issues.

The cooling system should be at a minimum pressure tested to determine the cause of the failure.

 

[Dave 2000]

I think causes have been covered, I used to be the avid gauge watcher but soon broke that habit, climbing 2000 metre trails around mountains barely the width of the 80 meant you watched where you were going! Like the oil pressure gauge they move without attracting attention, this is why I use a light and buzzer if anything steps out of 'range'. I actually did the temp gauge mod, it was from a MUD member, I cannot remember his name and thinking about it he has not been around for awhile? The mod worked great....no in fact it worked brilliantly, the gauge responds quite quickly to temperature changes, climbing a long hill 550 metre's from sea level will see the gauge move between just under 1/2 to just above 3/4, this would be at 38*C. Around this time my electric cooling fan kicks in and holds it around that 3/4 indication, the PWM fan has no need to increase it's speed. I spent considerable time testing when the fan switch operates, so know that is the actual temperature and not a guess.

I have been an advocate of electric engine cooling fans since the early 80's everything from a V8 MK1 Granada through to my present HDJ80, they were fitted to a range of cars including a V12 XJ12 C, not everyone likes them and I get that, mainly because so many people have tried them without actually doing their research and component selection in depth. All information will be found in my long running thread: Builds - My LC 80 thread. - https://forum.ih8mud.com/threads/my-lc-80-thread.365673/

regards

Dave

 

[DivByZero]

One thing missing above - check your viscous hub for your fan. That was the main source of overheating for my HZJ80 until I replaced it.

It's concerning that you say the coolant reservoir was overflowing. It could just be that your system was very full before overheating.... or it could mean head/head gasket failure pushing gas into your exhaust system. Coolant reservoir overflowing was the only sign I had that I'd cracked the head on my HZJ80 after overheating. Compression test was good.

Note that if you're going to do a combustion gas leak test on the radiator to check for exhaust gases, those are often designed for petrol engines, not diesel. With a diesel engine there's often not enough carbon monoxide in the exhaust to detect on those tests.

 

[Dave 2000]

I had not blamed the fan as I assumed being on the highway there would have been enough airflow to uncouple the fan? Still worth a check though.

Regards

Dave

 

[ScottJacob]

Thanks for all the advice folks! It turned out to be just a head gasket, which was annoying enough to replace. But thankfully the cylinder head was not cracked. After replacing the head gasket, my friend helped me install an aftermarket AEM coolant temp gauge and we also put a boost gauge on it as well. So, I currently have an aftermarket oil pressure, boost, and coolant gauge installed, and a pyrometer.

 

[ScottJacob]

Any recommendations on regular readings I should be getting on all those gauges for the 1HD-T? Oil Pressure, Coolant Temp, Pyrometer, Boost?

 

[mudgudgeon]

Any recommendations on regular readings I should be getting on all those gauges for the 1HD-T? Oil Pressure, Coolant Temp, Pyrometer, Boost?

Coolant temp, normal operating temp is anything from 74⁰C to 95⁰C.
If your gauge hits 100⁰C keep a close eye on it.
Your coolant didn't boil until about 110-120⁰C is you have good coolant, and a good radiator cap.

Oil pressure, at idle you should have 5psi +,
And at 3000rpm pressure should be 35psi +
More is better

Boost will depend on what turbo you have? Is it stock, or aftermarket.

Stock turbo, factory tuning, boost should peak around 11psi. If someone has messed with it, boost should not exceed 15psi. They become a grenade at some point above 15psi.

It turbo is aftermarket, max boost will depend on the turbo, and how it's setup.

Boost is not a constant. It's engine speed and load dependent.

Pyro. 750⁰c is widely considered to be a safe maximum EGT ONLY IF the probe is in the manifold before the turbo.
If the probe is after the turbo, all bets are off.

 

[mudgudgeon]

There's loads of info and chat about all this in the diesel tech section of mud

 

[Dave 2000]

The 1HDT in my experience is as tough as hell as they come from the factory, people forget performance versus engine longevity is not linear.

Any typical factory vehicle, lets assume say it has 100 BHP, it will last 400, 000 miles with reasonable care. Increasing power output by 25% can reduce engine life by 30% or more, increase power output by 50% and engine life could be reduced by 80%. And there are those that want even more, sometimes the result is an engine life of a few hours! Of course these are just numbers thrown out there, but you get the idea.

Despite having fifty plus years of building and racing engines, my 80 engine remains stock, given the isolated places I go I want reliability above all.

Regards

Dave