80 series engine temp?

Submitted: Friday, Jan 15, 2010 at 16:40
ThreadID: 75235 Views:5488 Replies:6 FollowUps:8
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Hi all, one for the Toyota owners.

I have an engine watchdog fitted to my 80 series 1HZ (no turbo), it normally reads 85-90 deg c.

I went up to Alice & back yesterday & it kept on hitting 100 deg c (I've got the alarm set at 100, very annoying).

Q: What is the hottest that I should let the engine get to? & what should I have the watchdog alarm set at?

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Reply By: Member - Fourplayfull - Friday, Jan 15, 2010 at 18:17

Friday, Jan 15, 2010 at 18:17
Hi Jeff, I have one in my 80 HD-FT with camper & all the extra weight but it only reaches 82 c in the wost situations.

I would suggest you have other problems. I have fitted a bigger 3 core radiator , new thermostat & waterpump which was not worn out though.

Then there is the possibility of a lazy fan clutch - check out Frank's post on 80's Offroad.com for exact details.

BTW under which stud or nut have you placed the sensor wire?

Cheers John
AnswerID: 399607

Follow Up By: Ozrover - Friday, Jan 15, 2010 at 20:02

Friday, Jan 15, 2010 at 20:02
Thanks John,

I've got the sensor under the thermostat housing bolt as they recommend.

I picked up new hoses & belts while I was in Alice, but forgot to get fresh coolant, I'll get a new thermostat & viscous clutch for the fan as well next time I go up there just to be on the safe side & flush the radiator out.

I'll see what happens then!

It's interesting that the gauge on the dash didn't move at all?

FollowupID: 668579

Follow Up By: Max - Sydney - Friday, Jan 15, 2010 at 20:24

Friday, Jan 15, 2010 at 20:24

I have had a 1HZ 80 series from new (1997) and the temperature gauge has NEVER moved from the same running position, no matter how hot, how fast, how much load and how much air con is running.

When it is under load, you should hear the viscous clutch operate the fan, that's a good indicator if you don't.

A car of that age operating in the hard artesian waters in the Centre could well have the radiator clogged up with lime. If a radiator flush does not help you my be up for a new core for the radiator.

All the best
FollowupID: 668582

Follow Up By: Max - Sydney - Friday, Jan 15, 2010 at 20:26

Friday, Jan 15, 2010 at 20:26
The hottest the engine will run at is the operating temperature of the radiator cap - about 113 degrees if I remember rightly. Above that it will boil.

FollowupID: 668584

Follow Up By: Ozrover - Friday, Jan 15, 2010 at 20:29

Friday, Jan 15, 2010 at 20:29
So I should set the warning temp at 110deg?

FollowupID: 668585

Follow Up By: Max - Sydney - Friday, Jan 15, 2010 at 20:56

Friday, Jan 15, 2010 at 20:56

Given that normal temperature is in the eighties (going by John's measurements which ring true - the engine is never very hot), I would not run mine anywhere near 110.

Maybe in an emergency, but I'd be stopping, raising the bonnet and letting the engine run at fast idle till it gets cooler long before it gets that hot. It will just put strain on hoses, thin the engine oil etc and lead to more trouble.

Most important, look for the real problem as per John's and discussions above as soon as you can get some radiator fluid.

FollowupID: 668589

Reply By: happytravelers - Friday, Jan 15, 2010 at 21:23

Friday, Jan 15, 2010 at 21:23
I also run a watchdog on an 80LC 1HZ no turbo. I've fitted the sensor to the housing where the top rad. hose goes into the head as I think this would be the hottest point of the engine. The thermostat housing is on the bottom hose on this engine as you will be aware. I've set the temp at 95 degrees and it has only gone off once, that was towing the camper over the Toowoomba range on a very hot day. You can easily tell by watching the gauge if the thermo fan hub is working ok. Mine will usually get up to about 90 degrees and then drop to about 78 after the fan has cut in before slowly creeping up again. If the thermo fan is ok I would remove the radiator and get it professionally cleaned out they do become partially blocked over time.
Regards Jon
AnswerID: 399637

Reply By: Member - Nick (TAS) - Friday, Jan 15, 2010 at 21:36

Friday, Jan 15, 2010 at 21:36
No point comparing factory temp. gauges to actual temps. as they have an inbuilt "dead" spot from somewhere like 50deg c to 90 odd deg c.This is inbuilt to keep owners happy.It can be made to work to show real time temps. and you will find the mod on LCOOL.
We run a watch dog on our 1HZ(DTS turbo and I/C), the hottest we have ever got it up to was 93deg c, towing our camper up a real steep, slow hill in 40 deg c heat.Normally it runs around 70-80 deg c.I have our watchdog set at 90deg c.
What was the outside temp?
AnswerID: 399640

Reply By: Ozrover - Friday, Jan 15, 2010 at 22:05

Friday, Jan 15, 2010 at 22:05
Thanks all, looks like I definitely have some cooling issues :( Time to spend some more money!

AnswerID: 399644

Follow Up By: Member - Fourplayfull - Friday, Jan 15, 2010 at 22:28

Friday, Jan 15, 2010 at 22:28
Make sure you only use the genuineTojo coolant - dilute 50% with distilled water . The sensor should be mounted on the thermostat cover as you need to monitor the water temp after passing through the rad.that way you know the rad. is doing its job or not. When on the top hose it will be hotter as it just left the head which is not a required reading.

Cheers John
FollowupID: 668600

Follow Up By: Outnabout.. - Friday, Jan 15, 2010 at 23:06

Friday, Jan 15, 2010 at 23:06
Hi John,
Haven't caught up in a while are you still with the houseboats?

Anyway back on topic. Probably doesn't matter where you put the sensor as it is a matter of knowing your normal operating temperature and then setting the alarm somewhere above that where you are comfortable. mine is on the top hose outlet as if the radiator does boil then it will boil at the hottest place, but as UI said it is just an indicator of change in temperature.
FollowupID: 668614

Reply By: Member - Phil G (SA) - Saturday, Jan 16, 2010 at 10:44

Saturday, Jan 16, 2010 at 10:44
Gday Jeff,
My daughter has the same vehicle (97 model) as yours with the probe from the Engine Watchdog in the same position as yours. She also had times when it read over 100 degrees. So we went through the cooling system and this is what we found:
- Thermostat removed and tested - it was opening at 81 degrees, (supposed to open at 76 degrees) and it would fully open at 95degrees (supposed to be 90). Replaced it with a new genuine thermostat (only $30).
- Radiator top tank removed and rodded - it was 60% blocked, and plastic top tank replaced because it had discoloured.
- grass, seeds and other garbage was removed from lower 1/3rd of radiator fins
- viscous fan removed, disassembled and found to have correct amount of viscous fluid.
- All new hoses and belts and a new genuine water pump ($180) while we were there. New genuine red coolant.

The temp readings are now always between 76 and 82 degrees. When pushed really hard it can get up to about 92 before the thermostat opens a bit further and it comes down.

At the very least, your thermostat needs replacing, if your temps are reading 85-90.

AnswerID: 399704

Follow Up By: Ozrover - Saturday, Jan 16, 2010 at 11:24

Saturday, Jan 16, 2010 at 11:24
Yep, going to see a radiator bloke in Alice next time we go there!

FollowupID: 668672

Reply By: trainslux - Saturday, Jan 16, 2010 at 11:50

Saturday, Jan 16, 2010 at 11:50
Things to look at are.

External blockages to your rad, and ac condensor, and between them can house alot of leaves etc that can block the rad.
No large spotties or other things blocking the air flow?

Is the fan shroud fitted correctly, no leaks between the shroud and the rad core.
Is the viscous hub working correctly on the fan?

If your on the open road, and it heats up at speed, this is usually signs of internal blockages in the rad core itself if the rest of the system is in good condition.

With presurised cooling systems, you can go over 100 C and up to the rated temp/ pressure on the cap.
If it was regularly over 100, with little load, and at highway speeds, I would be looking at getting the core rodded, and a flush if the other things are ok.


Ps, I did this mod to my hilux gauge and it was well worth it.


Link to the lcool cruiser mod at the bottom of page.
or here
AnswerID: 399716

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