Need Some Help

:frown: I have a 95 Chevy Corisca........6 cyl. It only has 60000 miles on it. The temperature guage would go way past the half way mark and slowey go over to hot. I had the thermostat replaced. It did it again today and this time I turned the heater on but when that didn't work I turned the ignition off. It took a couple of times turning the car off and letting it sit and then it was fine. It seems that the guage only goes over to hot when you first start driving it. Once I start the car again the guage is fine. This is when I am using the ac. I have had the mechanic check about everything and they cannot find out why it is doing this. Anyone have any ideas?????
Thank You

The two things that come to mind are (1) air in the coolant system. Have you guy bleed and burp the system in case you have a large air bubble in there. (2) I would be suspect of a bad temperature sending unit. They are cheap, see if your guy can take an actual temperature reading and replace the sensor if need be.

I had it checked again today and now they say it was the radiator cap. I hope this solves the problem. I'm thinking a bad sensor like you said or an air bubble but the guy who works on my car says he doesn't think so. He says if it happens again to let him know. If it does happen again I am going to ask to see if they can get any air out that is in the system and find out how much a new sensor would be. Thanks so much for your help. I do appreciate it.

I forgot about the cap. He might be right. A bad one or the wrong one will cause problems for sure. If that does not help then you can move on.

I'm sure hoping it is the cap. I have been going to this guy for about 10 years now and I have always been able to trust him. Just like when I took my car there and told him I needed new brakes. He called me back in a couple of hours and said I did not need new brakes that they had a lot of dirt on them and they took a powers air hose and cleaned them all off. I think he is pretty honest. Thanks for letting me know it could be the cap.