When the temperature in MN gets over 85 degrees, my Z28 gets very hot (260?)on the red line after I turn it off. Also, seems to run around 225. On cooler days it is about 200. I have never had a car so touchy about the outside temperature or move up so much when I shut off the engine. The system, coolant, fans, etc have all been checked out. Any thoughts?

 

If the temp gage red lines AFTER the engine is off it may just the heat rising to the top of the engine or the gage just likes to do that. Is the gage accurate? How long as this been going on, recent ? Are you running the AC a lot? Has the cooling system been serviced? Proper mixture of coolant to water?

 

Be sure that the coolant is sufficient. It may look full at the radiator, but there may be a pocket of air in the system. Make sure it's properly bled of all air, and also check for proper thermostat operation.

 

Thanks for the suggestions so far. We have looked at most of the suggestions, but will check em out again. Tomorrow, we are going to put in a new sensor and also look at why the fans aren't staying running when I shut the motor off. I'm not sure if they are supposed to, but need to look into it.I need to get it fixed while it is still hot in MN or I won't know if I fixed it or not, once the weather cools down.

 

That's no problem, move to South Central Texas where I am and you'll get to see if your cooling system works almost every day of the year. My fans don;t usually run after I shut the engine off though. Only once in a great while a really hot days and only for a few seconds.It cools really well but rarely do the fans stay on even in extreme heat. I have heard some people say the fans should stay on but I have never heard them stay on on any car in Texas except for a few imported ones. I asked one of my friends who is a GM Service Manager and he siad they don;t have to as long as the exgine is being proberly cooled. I have had mine on my 3.8 checked just because I wanted to be sure they worked OK. They definitely raor when both of them come on, usually when the AC is on and it's 100 outside.