Well, the climate control main line from under the hood on my 84 300d definitely leaks fairly quickly when I apply a vacuum. This is odd to me because I have pulled the plastic/wood over the climate control controls and the switches above them and tested all 5 lines from the switchover valves.
None of the lines leak, the one notable exception being the air recirculation pod (switchover valve 4), which seems to leak until it is fully open (the vacuum line going to it is REALLY small and it opens and closes very slowly for lack of airflow). I can't explain this. Anyone know what's with that?
I blocked off the line to the recirculation flap to keep it from having any impact, and theres still a leak. Could this be the switchover valves?

As a side note, my recirculation pod and defrost halfway diaphragms were bad, and the lines going to them are clogged.

bump

Could be a switchover valve. Test each one, energized and not enegized.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

99 W210 E300 Turbo Diesel, chipped, DPF/Converter Delete. Still needs EGR Delete, 232K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Gone and still missed...1982 w123 300D, 1991 w124 300D

Yup, it was one. It leaks when activated but not when deactivated. Thanks!