1989 633 csi Heating Problem

[woodrco]

Hello, I have recently purchased a 1983 633 csi. It is in great condition except for one problem, I recently discovered due to the cooling temperatures outside. My heater does not seem to heat up. The blower blows, but only cool air is produced. I checked the heating valve and found that the rubber seal was all worn, so I replaced it hoping that the heat would be produced. No luck. Does anybody have any suggestion? It will be greatly appreciated, I am getting tired of bundling up to drive my car.

[barry8108]

This may sound stupid, but check that they have not bypassed the heater core. Replacing the core is one of the hardest job's on a e24, and people will just bypass it rather than fix it. I had to do one and it was brutal. Worse than any job on airplanes! Also you will not get hot air out of the center vents. Heat only comes out derfrost or at the feet and this will fool people into thinking it does not work.

[Layne]

Heat only comes out derfrost or at the feet and this will fool people into thinking it does not work.

Since he's new here, I assume this is the problem. You just have to get used to the way 80's german cars work.

[madridcab]

Another common issue causing no heat is that the heater valve is stuck, easy replacement, do a search on heater valve..

[Brookfarm9]

DOes anyone know where or how to change a thermostat or where it's located...I have zero heat on my 1979 BMW 633 CSI ?

[DesktopDave]

The thermostat is located on the front of the engine, look for the aluminum heater manifold near the distributor. Here's a diagram: http://www.realoem.com/bmw/enUS/show...diagId=11_0690

Don't forget a new o-ring, it's part 8 in that diagram.

You might also have a problem with the heater valve or the valve actuator rod. Sometimes the rod will just fall off the valve. Since you have one of the early cars, you can find the heater valve near the pedal assembly, under the driver's side lower dash. It's a rotary valve, nothing special. Remove the kick panel under the dash and verify that the heater control dial is actually turning the valve. I uploaded a bunch of pics of an early HVAC control assembly on this eBay auction: https://www.ebay.com/itm/202520993287