Hey all, thanks again for your help. I replaced my thermostat as it was taking forever for my car to warm up. Now the problem I'm having is overheating, but I plan on bleeding the system and refilling. If that doesn't work, I imagine it's the water pump??? My other problem that I"m experiencing is that the heater blows cold. I've read on other forums that it might be the heater control valve, or possibly an ambient temperature sensor. Any advice would be greatly appreciated. I haven't been driving the car much this winter, so this problem may not have any connection to the thermostat issue I was having. Cheers! Sam THANKS TO YOUR AWESOME ADVICE MY CAR IS BACK ON THE ROAD, BLOWING WARM AIR IN THE CABIN AND NOT OVERHEATING. THANKS TO EVERYONE WHO RESPONDED. MY BMWCCA MEMBERSHIP JUST PAID FOR ITSELF AND THEN SOME!!!!!!
Try "burbing" it first What I do when filling coolant is WHEN ITS COLD! I take the fill cap off fill it to the brim... its going to spill out and all that but I leave the top off and let the bubbles work their way out. I hope its not the water pump. I also might be probalbe that the heater core is bad.
Presumably you'll get some more authoritative replies about other more likely possibilities, but it's possible to get a bad thermostat out of the box. Instead of one never closing, if it never opens, I'm guessing that could cause overheating. Knowing what year/model/etc you have might be helpful to others for armchair diagnosis. Various models can be difficult to bleed, E34's have an aux. electric pump for the coolant, etc., etc., lots of possibilities across the various models - Good luck w/ it!
Well, then test out the thermostat if you're unsure. It sounds like classic thermostat as it just happened to a car in our family; blows cold air and overheats. It's fixed now that it has been replaced.
The most common cause of perceived "overheating" after a repair such as yours is air in the system. But I think you figured that out already.
