Hi guys! Been reading alot of great stuff, but having some trouble finding some answers to some minor problems I'm having. I have an 88 IROC-Z 305 TBI Convertible. New engine, about 1200 miles on her. Been battling an issue that started with the temp gauge. According to it, the cooling fan is kicking on at 240 or 260, red-line area. The car doesn't overheat and the temp always goes back down. The heater also puts out a lot of heat at anytime, any temp when the heater isn't even on. I had the temp send unit replaced, the instrument panel gauge replaced, the board behind the instrument panel and the computer ECM was replaced when the engine was. Radiator is new. I can't be sure of the temp of the thermostat. I only drive this car in the summer and all I want to do is hold her to factory specs. Seeing that temp gauge get up there all the time is nerve racking! I will greatly appreciate any guidance and advice! Thanks!

 

I have the same temp gauge problem with my iroc. I have tracked mine down to be a voltage problem going to the cluster. Are you using sealant on the temp sender threads. If so, you might not be getting a good ground and could be throwing off the gauge. You shouldnt use any sealant on the threads. Getting heat all the time sounds like the blend door is open all the time or the door is not sealed when in the cold position. Check the cable from the heater/ac control to the blend door and make sure its hooked up.

 

Thank you for the fast response! I will check into the threads, the shop tells me that their computer when monitoring shows the system is functioning correctly, so maybe that it's it. On the blend door, where do i access that? Behind the stereo assembly?

 

You might be able to hear if the door is closing by sliding the hot cold lever back and forth. If it is closing, the heater box seals might be worn out or leaking.