W126 Warm Air

[design guru]

I have a W126 300 SE 91. The problem is the heater, it blows air when set to maximum but not very hot, only warm. The car heats up fine and sits nicely on 80º, but the heater only blows warm air on the first setting, if I turn the speed up to 2 or 3 it blows more cold air and you can just feel the warm air slightly. If I change the setting to the vents only it only blows cold air.

Not sure where to start looking, I thought it may be the thermostat, but the car heats up fine, any ideas where I should start?

 

[MBK]

its probably a stuck duo valve. Do a search for duo valve and you'll come across a very handy tutorial on how to clean (service) your duo valve.

K

 

[jaymanek]

Ive never managed to clean them without them getting stuck again, you will need new or second hand parts really.

 

[design guru]

Had a look on ebay, but otherwise not sure where to get one. I know there are threads on cleaning the duovalve, but I don't really have the time.