'93 318i Heater Problem - Cold/Warm Air

[PowerTrax]

Hello,

I just replaced my girlfriends thermostat in her 1993 318i BMW becasue it began to overheat. I noticed it quickly and I don't think it got hot enough to do any damage. So I replaced the thermostat, o-ring and housing gasket and it did the trick. It runs back where it was in the middle of the tempature guage. Unfortunately with the coming cold weather, the heater doesn't seem to be up to tempature. It usually blows cold or luke warm air even when the car is in the normal operating temp. I figured it was low on water, but it did not change much and it only took a quart. I don't know if its possible that there is something lodged in the heater core lines not allowing a steady supply of heated water. I would think there would be other cloges in the engine if that was true, but wouldn't that make the engine run hot? The other thing I read in another thread was air bubbles in the system. Could that be preventing much water from entering the heater core? And if so, do I just keep trying to add water each time I drive it? There is no leaking anti-freeze or foggy windows so its not leaking.

Any help would be greatly appreciated!!

Thanks

 

[selavia]

I was going to suggest heater core, but if no signs of leakage...

I don't think air in the system would contribute to the temp of air, but I could be mistaken.

 

[Laura-4-Lyfe]

I am not sure how the system works in the e30 but in my 280ZX the valve that allows water in to the heater core rusted closed. I replaced the valve and the heat started working again.

Good luck.

 

[E30m42cab]

Probably a good call... there's a valve on the firewall (assuming we're talking about an E36).