Off topic water cooling question ???

Hello, my other car is a 1994 BMW 320 i and I have noticed, in this really cold weather, that the heater blows hot when the revs are up such as when the vehicle is driving. As soon as the car slows and idles at a set of lights for example, the heater starts to blow cool air. Once revving again, the heater goes full heat again. Is this a low coolant problem, water pump, or leak in the system ?? Thanks for any advice.

Jerry S

1981 930
1994 BMW 320 I

Sounds like air in the system. You probably have some bubbles to bleed out. Could also be a thermostat problem. That is an '84 320i not a '94 right? I assume that's a typo. The 320i has a goofy inline t-stat with a built-in bypass for the heater core. That could be part of the problem. I'm a little rusty on the Bimmers but I think I'm correct on that. But definitely check coolant level first. That's a classic symptom of air in the system.

------------------
Tyson Schmidt
72 911 Cabriolet

Thanks Tyson, but the car is a '94. I am not sure if that model made it to the states but here in Canada we received for a couple of years a 320 I which is a 2.0 liter inline 6. I was considering your line of thinking and will try to investigate.

Thanks for the response

Jerry S

Very good whiskey and very fine autos have one things in common. Don't screw them up with water.

Randy Jones
1971 911

Wow Jerry, I hadn't heard of that one! A 2.0 inline six? Very interesting. Well the air in the system pertains to any water cooled car so..... Good luck!

------------------
Tyson Schmidt
72 911 Cabriolet

sounds like it's low on antifreeze.

Steve

vacuum controlled heater valve?? leaky?

------------------
Robert Stoll
83 SC
83 944