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sucky vacuum question

So I have been going through my 240 looking for any and all problems and taking care of them as I go. With my Mityvac (hand vacuum/pressure pump with gauge) I have been checking various hoses and systems on the car. It intrigued me that the line that goes from the manifold to the interior of the car that supplies vacuum to the ventilation system (operates through the defrost/recirculation buttons) to operate the various vacuum motors under the dash does not hold vacuum at all. Another 240 owner stated much the same thing. Now, do we have a problem, or is that the way they are supposed to operate? It seems odd that a vehicle that is so sensitive to manifold vacuum levels would 'leak' that much vacuum anywhere.

__ __ Randy & \ \/ /alerie's \__/olvos '90 245 Estate - '93 965 Estate "Shelby" & "Kate"

Reply to
Randy G.
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I've seen the vacuum resivoir behind the heater box split at a seam before, there's also a tangle of vac hoses behind the center console, one of them may have split or popped off. It should hold a vacuum well, though there's a fair amount of air to evacuate and if any of the buttons are pushed a vac solenoid will suck in so you may have to pump for a while but it should hold.

Reply to
James Sweet

Thanks, James. I was hoping that you would respond. Just knowing that the system _SHOULD_ hold a vacuum is a great starting place for me.

I did try 'pumping' the system quickly with the Mityvac but it rapidly returned to "0" vacuum. Looks like it is time to lay on the floor again. The Mityvac should make it an easy matter to isolate the problem. The various vacuum motors are operating as I can get defrost and recirculation changes... we shall see...

__ __ Randy & \ \/ /alerie's \__/olvos '90 245 Estate - '93 965 Estate "Shelby" & "Kate"

Reply to
Randy G.

You can try to isolate the problem by moving the vacuum switches, which will switch the "motors" out of the system, depending on switch position. If the problem goes away with a switch in a certain position, then you've narrowed the problem down to that leg of the system. If the problem stays for all switch positions, then the problem is in the vacuum supply side of the system.

Reply to
Mike F

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