intermittant loss of vac to interior HELP
 

Off and on my 190d looses vac to the interior = no shutdown or vent / heater control (defaults to hot). Trans shifts normally, brake booster functioning normally. I have the vac diagram for my car on cd, never can find the leak! Put a gauge on the vac pump, pulls a good vac. I have been tracking this down forever. I have changed all the rubber connections I can find, disconnected the heater from the circuit, removed all of the egr from the vac circuit, pinched off lines here and there. For a while, I had the heater disconnected and that at least let the car shutdown eventually. Had it all working for a while and today - boiling in my car in traffic and when I finally got home, no shutdown, in the rain.

What is the best method to find this problem once and for all?

anyone ever fitted a vacuum pump from a ford powerstroke (works heater and 4x4) or a saab (works cruise control) ??? I would just run the interior off it.

Gave up searching for the leak. Pulled a vacuum pump off an old volvo (for cruise control) tee'd into the supply line to the cabin and wired it to ignition. WORKS GREAT! car seems like it shuts down in less than one revolution and the heater is very responsive to temperature changes or vent changes. Very impressed with myself right now, lol.

It is probably not a leak, Sounds more like a blockage.