What would cause a 1987 Corvette to run hot at a red light?

restricted flow in cooling system stuck thermostat. I know many older vettes ran a bit warm. some people stuck a lower temp thermostat in them to keep them cooler. like a 160 to 180 rather than the 190 to 200

yes and i had an 84 that i took the thermostat out, but the 160 thermostat is good way to go, i currently have a 160 stat in my 99 WS-6, also check the electronic fans make sure they are both turning on, I have mine in my WS-6 to kick on at 180, so you can find some one to change the factor settings. Then basic, radiator flush.

I found a fan control system for 40 dollars on an offroad 4x4 website I will try to find where. I spend about an hour to figure out the wiring and about an hour to install it.

To answer your question, if it runs hot only when idling, you either have a bad fan switch or the fans are not coming on for some other reason. Observe whether or not the fans are on when it gets hot. Then turn the AC on. If the fans run while the AC is on then you most likely have a bad fan switch.

I'M NO MECHANIC, BUT I LEARNED LONG AGO ALWAYS LOOK FOR THE SIMPLEST, STUPIDEST THING (S) FIRST.

I have an 87 corvette that is overheating and the fans wont turn on. I have replaced the fan motor, fan relay, cooling temperator sensor (on the passenger side block by spark plug) a new thermostat, and some wiring. My fans still wont turn on. Im currently flushing the radiator out. I did get the fans to turn on at one point but now its not working. Im loosing my patients BIG TIME! I dont use the AC because the system needs freon (and compressor seal) which I cant afford at this time. But that shouldnt stop the fans from turning on right? WHAT AM I MISSING?? PLEASE email me christina.ghosoph@gmail.com

I hope its not the thermostat because its such a bitch to remove the inlet.

according 1987 corvette manual temp can reach 250 and that's ok hope that helps.