1HZ (diesel) coolant temperatures? (1 Viewer)

[dmarsc10]

Yes, as long as you are sure thats the problem



You'll have to take the radiator cap off under pressure, not my favourite job.
Thats why I suggested the infra red thermometer

Looks like that'll be my next mission.... get a real/definitive temp measure directly on the coolant and compare that with what my gauge says...
Thanks again for the advice mate...

 

[mudgudgeon]

Thinking the thermostat might need replacement...
Possibly not opening fully??

It's worth checking, or replacing. It's not a huge job to take it out, but by the time you have it out to test it, you may as well replace it.

I have tested an old OEM thermostat and found it started to open when it should, but didn't open fully until well above the specified temp.

Radiator and fan hub are probably the two main things you need to have 100%

Thermostat and radiator cap are also important

Don't pull the radiator cap off if you've got water temps over 100°c.
The radiator cap is supposed to keep the system pressurised which means the water can be super heated above boiling point without it boiling.
Releasing the pressure can see water instantly boil.
Watching a radiator puke its guts out with a steaming fountain of coolant in 30 seconds after you've popped the cap is interesting.

 

[dmarsc10]

It's worth checking, or replacing. It's not a huge job to take it out, but by the time you have it out to test it, you may as well replace it.

I have tested an old OEM thermostat and found it started to open when it should, but didn't open fully until well above the specified temp.

Radiator and fan hub are probably the two main things you need to have 100%

Thermostat and radiator cap are also important

Don't pull the radiator cap off if you've got water temps over 100°c.
The radiator cap is supposed to keep the system pressurised which means the water can be super heated above boiling point without it boiling.
Releasing the pressure can see water instantly boil.
Watching a radiator puke its guts out with a steaming fountain of coolant in 30 seconds after you've popped the cap is interesting.

Cheers mate....
Next chance I get I'm going to put a new thermostat in.... just for piece of mind.... it's definitely opening.. but perhaps not fully??
I'm sure it's not hard to do.... just harder to access with alternator and turbo intake pipes etc, in the way...

 

[dmarsc10]

Ive only ever replaced a t/stat with the engine out, but I don't feel its a difficult job in. Im not sure you need to remove the alternator, but that's a job that gets easier after a few times.

I test the t/stat by hanging onto the top radiator hose from a cold start. When the t/stat opens from a fast idle, you can feel a flow of warm coolant through the hose if its working ok, it takes about 5-10 minutes. But its a definite change of temps and will get warmer.

Hoses should be firm, not rock hard. Rock hard is a often a sign of a head gasket leak.
Pressure in the system stops big steam bubbles forming around the cylinders. Once bubbles form in your cooling system basically throws its hands up and surrenders.
A bad rad cap is often the root cause.

The position of your sensor is right in the cylinder head.
I'm wondering if its giving you the temperature of the combustion chamber rather than the coolant. Temperatures in those areas get a lot hotter than the coolant.
Normally the sensor is on the coolant outlet where the top radiator hose connects to the head.

Did anyone alter your injector pump fuel settings when the turbo went on?

After an hours drive this arvo where my temp gauge showed 100c at times... (towing a smallish boat)... I returned home... idling, it consistently sits at 90c... I carefully removed the radiator cap and measured the coolant directly with a bbq thermometer... 80c.

I'm thinking the sensor location (in the cylinder head) is why my readings are the way they are... and my cruiser isn't running hot at all??

 

[roscoFJ73]

I think you have it sorted. You want the temp of the coolant leaving the cylinder head , like Toyota do it.