Do you have steam blowing on the inside of your windshield on your BMW 2002?

Does your passenger complain of being in a steam bath?

Are your socks soggy? Perhaps you have a leaking heater control valve.

Open the hood and look in the compartment under the windshield on the passenger side. The brass oval fitting with two large screwheads is the heater control valve and housing.

To repair heater control valve:

1. Open the heater control lever to full heat and note the position of the lever on the back of the valve. Using a 7-mm box wrench remove the lever only from the brass housing. Do NOT disconnect the Bowden cable from the lever. (A real Bite to replace and reconnect if you do.)
2. Remove the two slotted screws from the valve housing with a large-bladed screwdriver.
3. Pull (pry, rip, etc.) the cover off the housing trying not to chew up the large sealing “O” ring gasket. Remove valve from housing.
4. Remove mangled “O” ring from the valve stem and replace with a new 5/16″ id “O” ring from your hardware store. It should be black neoprene.
5. Lubricate with a silicone grease (wheel-bearing grease will do) to preserve and seal the new “O” ring and the large sealing “O” ring gasket (of step #3 “rip, pry, etc.”).
6. Reassemble, checking to be sure that if the inside control lever is on full heat, the large hole on the valve is horizontal. This lets the coolant flow to the heater core. Do Not Over tighten.
7. Check for leaks at normal operating temperatures. There should be none.

Author: Bruce Zepke