Air vents hot with heater off

[mantis73]

My 1988 535i (E34) seems to add some heat to the air circulation (if outside temperature is 70 F air vent will be above 90 F if engine is hot). Heater valve incoming water hose is closed and no water is flowing into the heater. Also I set fresh air and recirculation flaps into recirculation mode and disconnected the harness plug. Diesel smell comes inside whenever I am driving behind a bus even with closed windows. Any ideas on where this heat and smell are coming from ?

[eightynine535]

bump

yeah does anyone know?

[meechz]

I'd check the heater control valve, when they go they will cause these symptoms. There're located on the firewall on the left side when facing forward the car

[mantis73]

Hi all.
After taking the car to so many garages with no use I decided to fix it myself. I removed the entire heater box and took it home (after removing half the car's plastic). Fresh air doors were not closing completely plus there were big cracks on the blower casing. This was drawing hot air from outside and preventing full recirculation mode. To make things worse, the climate control system was customized by a previous owner to add airconditioning. The inside half was from the original BMW valeo heater and the outside part (evaporator, blower, fresh air doors) came from an unknown car !!! As the evaporator was leaking refrigerant within a week, I had to replace it. The best match was an Aluminum from a 3er. The new evaporator however required lots of modification to the orginal casing. I did this by using a tyre tube to patch around the evaporator. I reinstalled the heater box, connected refrigerant hoses and used a workshop only to fill gas (which is the only thing they do best). The system now works very well.

[eightynine535]

did you take any pics of the box and fresh air doors to show where they are located?

[mantis73]

No I did not take any photos unfortunately.

[eightynine535]

so where is the fresh air doors located?

[clevertd]

Heater/Air-con then Center Vents
http://bmwe32.masscom.net/

[mantis73]

Great link !

[eightynine535]

this should be FAQ'd!!