I just wanted to pass along something strange that I was able to resolve with the tips for here...... My 95 Legacy, which has 240K miles, began acting strange lately. The heater would warm up and blow hot air, then cold air, then hot air, ect as I was driving. The temp guage never left the nortmal position, and I was getting quite aggrevated by it. I have done all routine maintenence since I bought the car new. It has recently had a new timing belt, water pump thermostat, ect done, before the weather got cold. Then I noticed this problem with the heater.

 

With some tips from here and a few other net sites I found doing a search, I found that maybe it was a thermostat, or possibly a head gasket, although nobody described my problem exactly. One person recommended getting rid of any air in the colling system to help eliminate some coolant related issues, and mentioned that it should have been done after any work was performed on the system. Since I had recently had this work done on my car by a new mechanic, I thought I would give this a try, and IT WORKED!!!!!!

 

I put the car on my ramps on the steepest part of my driveway (about 15 degrees) with the front end high. I then removed the radiator cap, and the lid from the resevoir bottle. I ran the car at about 2000 RPM witht the heater on high unitl the thermostat opened and the radiator basically drained. I could see no coolant in it. I also squeezed the hoses repeatedly to try and push all the fluid into and through the system. Then I revved the engine to over 3000 RPM a few times to pull through as much as possible.

 

I then turned off the car, and began to slow fill the radiator again. It would get full, and then the air bubbles would flow to surface and the level would go down again, so I would add more, until it stayed full and no air bubbled out. I then put the cap back on, and closed the resevoir after amking sure the coolant was filled to the line.

 

After driving it for about 2 hours, the heater temp never fluctuated, and I lost no coolant, couldn't smell any coolant, and the temp guage stayed pegged in the center as it always has.

 

Thanks to all the guys who post tips here, and if anyone else is experiencing this type of issue, I hop emy experience helps!!!!!

Hard little suckers to fill with coolant. I've used a Mighty Mite hand vacuum pump to to suck out trapped air from the radiator bleed vent with the radiator cap on because I had the same problem.

Do you know if they used an OEM thermostat when replacing water pump & t-stat?

 

That can also cause you some probs if they used an aftermarket kind.