How high does your temp gauge go after shutting car off and those few seconds turning it back on?

[rogerwilco]

I noticed sometimes after a long ride if I shut off the engine, come back to the car a minute later and start engine, the coolant temperature gauge sometimes goes way up. Usually it just goes up a little over half, sometimes 3/4, one time I saw it almost near the red zone. After a few seconds of turning the engine back on it goes right back to normal down below half where it should be. Is this normal?

I sometimes hear a low speed fan running when shutting off which is a good thing but allot of times I don't hear a fan. So I am a bit concerned that maybe the fan is not coming on when it should after shut off?

I recently had a blown head gasket fixed which cost me a fortune and do not want to risk blowing it again. At that time I replaced the temp sensor at that time with a Driveworks one.

The car does not overheat and runs at normal temperature when driving. I put in a new water pump and as a precaution replaced all 3 fan relays and fuses.

 

[melsg5]

Are you sure all the air was bled out of the cooling system?
It's expected that the temperature would increase after shutoff but near the red sounds like too much?
When completely cold is the coolant level at the correct point?

 

[rogerwilco]

I wonder if it auto bled since that one high reading I had. The last few times it was a little above half (which I think is normal after shut off) and one time 3/4 of the way (not sure if that is normal). I may give bleeding it a try at some point if I see it 3/4 or higher. Even if it was an air pocket I thought that the fans should kick in when off. Seems only to do it intermittently when off and a concern when it was up high when off, the fan did not come on.

When cold it is correct and also shows correctly below half when driving. Only when I turn it off and wait a little, then turn the key to see where it is at does it go up.

 

[cammerjeff]

It is normal for the coolant temp to rise after shutting down a fully warmed up engine. It can raise 50F degrees. When you shut down the engine, it loses the coolant circulation around the block and the heads when the water pump stops turning.

On a modern car like your Montana with electric cooling fans on the radiator it should raise less as you still have a few minutes of air flow from the cooling fans after you shut the engine down.

do you hear the fans running for the 1st minute or so after you shut off the engine? If it does not get over 250F, and if it starts to come down almost as soon as you start the engine I would not worry about it. That is if the cooling fans are still running when you turn off the engine.