I have a newly acquired 73 220D that the heater blower works at all three speeds but no warm air comes out of the vents even after driving for a long period of time. One thing that might be related is I have noticed my normal operating temp never reaches past 175F according to the gauge even if I let that car idle for some time and when driving down the highway it likes to stay in the 140F area.

I remember one of my old E30's had the wrong thermostat installed and the car constantly ran cool and the heater blew cool air until I changed it to the correct thermostat so I'm thinking this might be a similar situation?

Probably the plastic mono valve on the firewall near the brake booster....some of them have a screen, it gets clogged up....sometimes the valve needs to be rebuilt.....there are cables running to it....one may have popped off....

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I gave the mono valve a quick look this morning and everything looks connected correctly and tight. Now Im going to open it up and see if it has a clogged screen. Thanks cooljjay

What did you find ?

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1971 250C Ivory / Cognac Leather ~ 1993 500E - 040 / 271 - Porsche Type 2758

Past Cars - 1994 E500 - 2003 CL600 V12TT by SPEEDRIVEN - 1994 E500 - 1995 E320 Cab - 1988 BMW M6 - 1994 E320 Cab