When driving around town (i.e. sitting in traffic, going less than 40 mph, etc) I find my car's temperatures getting dangerously high. I'm talkin 245-250 at times. But just when i think i'm going to overheat, the the temperature slowly goes back down, until i make another stop, then goes slowly up again. I've had the radiator and water pump replaced within the past year at a chevy dealership. They pressure test the cooling system, and don't report any leaks or abnormalities to me. Do you guys think my fans could be malfunctioning, or coming on too late? Or maybe a T-stat issue (i had it replaced 2 years ago so it could be stuck). I read another post about the car's heater being an issue. My car's heater doesn't really work either, so could this be a cause for my car's high temps? When I'm on the freeway, my car's temp stays around 215, is this normal? And finally, what do you guys think about manual fan switches?

Thanks

 

Had the same problem with mine. Had it flushed/filled. Replaced the overflow and thermostat and bled the system constantly. A shop took off the radiator cover and there were a bunch of leaves and dirt that had built up in the radiator fins. I didnt have a way to blow it out so they did and cleaned it with water also. Since then it hasnt even come close to halfway and I went from a 160 stat back to a 180. Now it can sit in traffic all day with the Ac on and no problem, and I live in Phx with 110 degree days

 

but I just had my radiator replaced about a year ago...i don't think the fins have build up already. any other suggestions?

 

really depends on how dirty/dusty the conditions are where you live. clean it well like i mentioned and see if that helps you at all. it was getting so hot and boiling the coolant out it caused my low coolant light to come on. hasnt even blinked since i did that to it.

 

Also make sure *both* cooling fans come on. My old z28 had only one of the fans coming on, and the other never came on for some reason. It sounded like the cooling fans were working, but it wasn't until I got under the car and watched them, that I found out. I don't think just one fan can bring temps down.