Potential heating problems, need help

[Mest30]

So I'm driving to my local Post Office this morning (only a few miles from my house). I go in, pick up my package and leave. About a mile after I leave, the car's water temperature was way high, all the way to the 'H'. I pull over as soon as possible because I didnt want the car to over heat. Of course, I left my phone at home so I cant even call anyone for help and my car knowledge is lacking at best. I check the coolant level and it seems fine. So I wait about 20-30 minutes and decide to drive home and pull over to let the car cool down as needed, seeing as how I was five minutes from home. Of course, I get stuck by every red light. So the car's temp goes all the way up to the H again (it usually is in the middle) so I get ready to pull off the road again. As I'm looking for the nearest driveway, the temp goes down rapidly to it's normal operating temp. It did this in a matter of 3 seconds. So I dont stop and just go home and everything is fine. I leave for work a few hours later (work is a 20 miles drive) and everything is fine. So I'm stumped. Do they gauges have a habit of malfunctioning? Any help is appreciated. Thanks.

[BlackIce]

It's possible you have some air in the cooling system that is preventing the proper flow of coolant past one of several points. You can bleed out any excess air in the system by opening the vent cap on the crossover tube and letting the car run, while pouring coolant into the opening until the cooland spills out. I believe the engine has to be up to normal operating temp to do this, but it can't hurt to check while it's cold too.

[B.C. Bake]

Or your thermostat might have stuck closed for a moment?;)

[Mike]

It's possible you have some air in the cooling system that is preventing the proper flow of coolant past one of several points. You can bleed out any excess air in the system by opening the vent cap on the crossover tube and letting the car run, while pouring coolant into the opening until the cooland spills out. I believe the engine has to be up to normal operating temp to do this, but it can't hurt to check while it's cold too.

^^^ I would have to agree^^^^^

[Mest30]

I could have an air pocket, but I doubt it. When my friend changed the water pump, we had an over heating problem because we didnt bleed the system properly. Once we figured out what was wrong, we got rid of the air pockets and it was good to go. That was 3-4 months ago. And the t-stat is brand new. It got installed about 1-2 months ago.

[Zack]

Air pockets can remain 'hidden' for months, like what happened today.

Your cooling fan may also be the culprit.

[Mest30]

Ok, so I'll try bleeding the system again. How would I know if it's the fan? If the problem happens again, what should I do? Pull over again? Keep driving and hope it corrects itself again?

[jgc61sr2002]

Ok, so I'll try bleeding the system again. How would I know if it's the fan? If the problem happens again, what should I do? Pull over again? Keep driving and hope it corrects itself again?



I also suspect air in the system.
I believe the fan comes on when you put the temperture control in the A/C detent.

[Aren Jay]

Don't keep driving just in case it is overheating.