I just bought a 1997 Camaro Z28 and thought everything was fine until I decided to run with the windows down and no A/C. The thing ran hot (230 deg). I noticed that the fans werent coming on if the A/C wasnt engaged. I replaced the thermostat and coolant along with all three fan relays. By the way the old coolant looked kind of gummy. Well now the car gets up to 215-220 deg range when idling and only one fan engages, when I turn on the A/C the car runs 180 deg and holds ( I put in a 180 deg thermostat). Any suggestions? How can I make sure that I get all that gunk out of the cooling system? The radiator flows fine, I can see it cycling water with the cap off.

This probably won't fix your problem, but GM reccomends a 195* t'stat or the polution control stuff will not work properly, causing you problems ! If the computer is reprogrammed with a Hypertech Program or equivalent, it can be done.

The fan is not supposed to come on until about 220. There is probably nothing wrong with your system at all. Most new cars run at about 200-210 under normal conditions.

Most gm cars run a bit on the warm side for emission purposes buy yourself a Hypertech power programer and you can go in and bring the cooling fans on at a lower temp and switch to a 180 degree thermostat