1994 325 is overheating, heater cold

[virginia]

We just bought a 1994 325 with 138,000 miles. We drove the car back home 2000 miles and it drove fine. We had it two days and it's now running hot and stalling. The interior heater is cold. We replaced the thermostat and removed air bubbles from hoses. It still gets hot. Does anyone know what else we can try? Thanks for any responses.

[freniv]

I've got a 1995 325ic and had to replace the water pump. I'd suggest that you make sure your water pump isn't defective. They came with plastic impelers on a metal shaft. After a while the plastic would spin off the metal shaft. Thus the fluid won't circulate and you won't get any heat. I found mine too late and it cracked the neck off the rad. Failing that your heater core may be plugged. My first guess would be your water pump as everyone has issues with the pump impellers failing.

Goog luck

[virginia]

Originally Posted by freniv

I've got a 1995 325ic and had to replace the water pump. I'd suggest that you make sure your water pump isn't defective. They came with plastic impelers on a metal shaft. After a while the plastic would spin off the metal shaft. Thus the fluid won't circulate and you won't get any heat. I found mine too late and it cracked the neck off the rad. Failing that your heater core may be plugged. My first guess would be your water pump as everyone has issues with the pump impellers failing.

Goog luck

The water pump was toast. The plastic was erroded, soft and the shaft was spinning without the impeller. No cooling flow for the engine or hot water for the heater. I also found the thermostate was not openin all the way which made the heater slow to warm up prior to it totally stop working.

The impeller material choice is poor and anyone with the plastic part should replace it as soon as possible to prevent overheat damage to your engine. It is a fairly easy fix, provided you can get the fan nut loose and have the two metric bolts needed to ease the old pump out of the engine. NAPA sells a new pump with the metal impeller for about $65. Overheating, damage to the cooling system including radiator replacement seem to be very common problem for the 3 series with these poorly designed pumps.

Thanks