hahahhahhaha lmao. the first thing i thought when i read the first part of ur post was......NOT AGAIN![:@] lol. but that was a good one.

 

Hello....I have a 1996 3.8 Mustang (150k miles) located in NJ. I am having the same problem with overheating and cold air blowing from heat duct. I had the head gaskets replacedand re-manufactured heads the being of summer 07'. Car ran fine no overheating problems all summer. As soon as it got cold and I needed to use the heat the problems began. It is a intermittint problem, I changed the thermostat , also the belt , had the system pressure tested (it was fine , no leaks). I checked the fluid level and it is also fine. The engine warms up to the N in normal range. I turn on the heat and it works fine then 10 miles later it is blowing cold air and I notice the temperture starts to rise. It raises to about theL in normal than a a mile or two it goes back down and the heats returns to hot. I checked the fluid level when I got to work and the fluid overflow bottle was overflowing. The radiator was to hot to check, I went out a few hours later and the fluid level is ok in the radiator and the overflow bottle went down to about 3/4 full. I started the car with the radiator cap off and warmed the car up and saw the fluid start to flow once the thermosat opened I checked the temp gauge and it was on the N in the normal operating range. Water pump does not make any noise so I am guessing the bearings are ok and no fluid is coming out the weeping hole. Does anyone know what the problem could be? Your help would be appreciated because I think the garage I take it too doesn't have a clue nor do I?