Hogg5.0GT

i just recently bought this 94 gt, only has 64000 miles, all original, shortly after i got it i noticed it was overheating pretty severly. i had similar problems in my 96 mustang v6 and it was the thermostat. So i replaced the thermostat in the gt and it ran fine for a while, just the other day it started to go from fine to all of a sudden bouncing up and then it would go back down. dont know what it could be. my a/c wasnt working and i realized that it wasnt plugged in, so i plugged it in and it worked great. ever since i plugged my a/c in is when the temperature guage bouncing started. its not leaking anywhere that i can see, if anyone can help me out it would be greatly appreciated. Could the " exhaust heat solenoid unit" be the cause? i got that out of a prior check engine light code?

projectresto83

Is your fan kicking on?

Tha Boss

Check water, fan, water pump, etc.