Outer Limits 4x4 Board

Hi all

Recently finished bolting up a turbo to my 2H. Started it today - runs fine. Haven't touched the fuel yet, and the boost max's around 7psi. Had the radiator out so recently dumped all coolant and re-filled. Car hasn't been run in a couple of months (maybe more) previous to today - never any serious temp problems before.

After a very short run up my street (about 500m), and idling for a couple of minutes max, i noticed the radiator top tank was too hot to touch. The gauge still read a low temp. I let it cool then needed to turn it around in the drive - max 3 mins running basically at idle - and again the engine bay was very hot incl. rad top tank. Top hose seems to have decent pressure (as did the cap when i pulled it off 5 mins after shutting it down). I haven't been game to take if for a decent run.

Do you think this is too hot after such little running time? It seems about as hot as it would be after a long trip (haven't had it running much in the last year so hard to remember how hot it used to get) What could cause this? I suspect the gauge may be faulty. Could a sticky thermostat cause be the problem? Could it be excessive backpressure from the turbo or manifold? (ARB manifold/GT2860RS)

Could it be anything to do with draining/refilling/refitting radiator? (also drained motor)?

Pump rotates smoothly, fan appears to work properly still.

I don't imagine it would be due to the boost as it's only seen boost a couple of times, for a few seconds each time.

Any ideas?

I'll buy a new thermostat/temp sender/gauge tomorrow and see how it goes, but would also like to hear any opinions out there

-Stu

Is the fan sucking? Or blowing? It it's at operating themp, you can't usually touch the top tank for too long.

I doubt it will be the thermostat. It stops coolant getting out of the block.

Test the sensor for resistance with a multimeter.

joel HJ60 wrote:Is the fan sucking? Or blowing? It it's at operating themp, you can't usually touch the top tank for too long.

I doubt it will be the thermostat. It stops coolant getting out of the block.

Test the sensor for resistance with a multimeter.

Good thinking, thanks.

What is the acceptable operating temp range for the 2h? The sender is to be tested at 50 and 115 deg C

dogbreath_48 wrote:

joel HJ60 wrote:Is the fan sucking? Or blowing? It it's at operating themp, you can't usually touch the top tank for too long.

I doubt it will be the thermostat. It stops coolant getting out of the block.

Test the sensor for resistance with a multimeter.

Good thinking, thanks.

What is the acceptable operating temp range for the 2h? The sender is to be tested at 50 and 115 deg C

Coolant operating temp?
I'd imagine very close to or just over 100C with the thermostat opening at around mid - high 80C

joel HJ60 wrote:

dogbreath_48 wrote:

joel HJ60 wrote:Is the fan sucking? Or blowing? It it's at operating themp, you can't usually touch the top tank for too long.

I doubt it will be the thermostat. It stops coolant getting out of the block.

Test the sensor for resistance with a multimeter.

Good thinking, thanks.

What is the acceptable operating temp range for the 2h? The sender is to be tested at 50 and 115 deg C

Coolant operating temp?
I'd imagine very close to or just over 100C with the thermostat opening at around mid - high 80C

That was my thinking.

Putting a new thermostat and VDO gauge/sender in today - see how it goes.

-Stu

Put a new thermostat in my 2H the other week, I think it was 88*

dogbreath_48 wrote:

joel HJ60 wrote:

dogbreath_48 wrote:

joel HJ60 wrote:Is the fan sucking? Or blowing? It it's at operating themp, you can't usually touch the top tank for too long.

I doubt it will be the thermostat. It stops coolant getting out of the block.

Test the sensor for resistance with a multimeter.

Good thinking, thanks.

What is the acceptable operating temp range for the 2h? The sender is to be tested at 50 and 115 deg C

Coolant operating temp?
I'd imagine very close to or just over 100C with the thermostat opening at around mid - high 80C

That was my thinking.

Putting a new thermostat and VDO gauge/sender in today - see how it goes.

-Stu

How did it go Stu?

did you bleed the air out of the cooling system after changing???

replace thermostat and gauge sender!! then check the bottom and top hoses and compare the heat difference. if top hose getting much hotter then bottom either radiator blocked or waterpump impellor rusted out. feel radiator for cold spots to confirm a blocked radiator. a stuck thermostat will still allow hot water into the top of the radiator. it wont however allow much cool water to be drawn into the block. if its overheating in under 5 mins it most likely thermostat

VDO gauge shows it's operating normally (80-85 after a longer run). Looks like i was overreacting a bit

Still, thanks for the advice Jacked - good diagnostic information!

How does one go about bleeding the air out of the system? Toyota's own workshop manual mentions nothing of it. I normally just run the engine for a few mins with the rad cap off.

-Stu

Hey stu,
Remove the heater hose off the highest fitting in the cylinder head. It is higher than the rad cap. Fill cooling system through heater hose until water comes out of fitting in head bleeding air out.

Dan

Ruffy wrote:Hey stu,
Remove the heater hose off the highest fitting in the cylinder head. It is higher than the rad cap. Fill cooling system through heater hose until water comes out of fitting in head bleeding air out.

Dan

Thanks Dan I assume it's the big stalk out the middle of the head? I suppose that's why it's there - interesting that the workshop manuals make no mention of it!

-Stu

joel HJ60 wrote:Is the fan sucking? Or blowing?.

I dont under stand how do you make an engine driven fan blow?unless you change the engine rotation

If you bolt it on back to front it will still suck just not as hard because the blade pitch is all wrong


thrashlux

thrashlux wrote:

joel HJ60 wrote:Is the fan sucking? Or blowing?.

I dont under stand how do you make an engine driven fan blow?unless you change the engine rotation

If you bolt it on back to front it will still suck just not as hard because the blade pitch is all wrong


thrashlux

Your right it will still suck but not as effectivly have a look at a fan blade it is supposed to go on one way.