[I_CTCHR95]

I have a 1995 V6 Mustang and recently have been dealing with some behavior that puzzles me. For a few days, on and off, my car started overheating. It only happened every few days, so I replaced the thermostat. After replacing the thermostat the car hasn't overheated, but after the car has a chance to warm up the temperature will begin to flucuate. This doesn't happen all the time, and never seems to happen when I make my boyfriend drive it. I am aware of the problems that 1994-95 V6s have had with head gaskets, I've already replaced the engine once. The engine I currently have have about 80,000 miles. I'm not losing water, my heat is fine, in fact other than the flucuation the engine feels fine. The only problem I am having is with my muffler, which has begun rattling due to a bad installation. Any ideas or am I out of luck and a lot more money?

[99mustang232]

what tempeture thermostat did you install? once the vehicle is up to temp can you feel warm fluid being circulated through the hoses? i assume you did a coolant flush when replacing the thermo...did you check to see if there were any air bubbles in the system after replacing the thermostat? make sure your fan is working, also make sure the fins on the front of the radiator are not clogged. might wan't to try replacing the radiator cap, beleive it or not a bad sealing cap can cause numerous problems... and if you said the engine has once been replaced maybe you kept the original radiator and what not...