Heater/AC vacuum diaphrams.

[mavtricks71]

Holy Moly! Im doing the Heater core on my 1986 k10 with A/C...um yea what a project. OK There are 2 black vacuum diaphrams connected to the heater core box ….Do these ever go bad? just wondering because im never pulling the box apart again it's a bit of a nightmare.

 

[1987 GMC Jimmy]

All my vehicles have those diaphragms and none of them have ever gone bad that I know of. I’d like to think they’re pretty hardy, but I seem to recall some people not having the same good fortune. I’ve been wondering this myself and look forward to the feedback.

 

[mavtricks71]

Yea ive never had them go out any any older vehicles. If they do go bad the are bolted in from INSIDE the heater core box so it will have to be taken all apart just to change them. Pretty dumb they should design it to bolt on from the outside!!

 

[Craig 85]

Yes they go bad. I had to replace the one in my last truck. Of course it was the one inside the heater box. There are actually 4 vacuum pods. Two on the box, one at the passenger kick panel and the 4th under the cowl screen.

The first diagram is for a fuel injected truck, but the A/C part of the system is correct.

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[mavtricks71]

Wow I wish I had a printer ….I need to print this off somehow.... Thanks