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I replaced the plenum gasket and TB-to-Plenum gaskets in my '82 yesterday. Turned out a previous owner had already done this job, but I couldn't know that until I went in. Anyway, I've been fixing cracked and disconnected hoses in the engine compartment, and I found another one during my work. This one is attached to a valve in the heater hose on the right side of the motor (photo below). The hose is flexible plastic with a white stripe. It was routed up toward the distributor, but just hanging loose. When I looked around the area, I found a small cluster of rubber vacuum lines exiting the firewall in that area. One was empty, so I attached the hose there. I'm not sure what this valve does (heater shutoff?), but can someone confirm that this is the correct connection for the hose?
before attaching it at the firewall you should test the firewall hose to see if it has vacuum when the controls are set for heat on or off to make sure the hose isn't a vent and is supposed to be open
click on the link below for a diagram of the hoses http://repairs.willcoxcorvette.com/1...uum-schematic/
That valve is definitely aftermarket. It is the hot water shut off, there is a vacuum plunger on top of the air box that is activated when the temp lever on the a/c controls is all the way on cool that closes that shut off valve to keep hot coolant out of the heater core. You may want to check that vacuum switch under the passenger side dash as well. You can get to it by pulling the glove box.
Just to be sure I understand... this is an aftermarket replacement for a shut-off valve that's been removed? So the unused firewall vac hose I found is probably supposed to be connected to this? I can check that hose to confirm vacuum isn't present on AC or Max AC.
Yes, that is correct. But the vacuum should not be present when the temp lever is all the way to Cold, regardless of what is selected, A/C, Max A/C or heat.
That striped-white hose ultimately goes through the firewall via a grommet in left side of the firewall (driver's side) very near the distributor. I changed my vacuum hoses with a Willcox kit this year and recall this hose because I clipped the old one off near the grommet and used a fitting (came in the kit) to attach the new white-striped black hose to the old one where it enters the grommet, saving me from feeding the new hose through the firewall grommet. Mine is in storage so I can't go look at it but it either provides the vacuum to the headlight switch and/or the climate controls once through the firewall and into the cabin.
'82 Vac Hose - Correctly Connected?
Anyway, I've been fixing cracked and disconnected hoses in the engine compartment, and I found another one during my work. This one is attached to a valve in the heater hose on the right side of the motor (photo below). The hose is flexible plastic with a white stripe. It was routed up toward the distributor, but just hanging loose. When I looked around the area, I found a small cluster of rubber vacuum lines exiting the firewall in that area. One was empty, so I attached the hose there. I'm not sure what this valve does (heater shutoff?), but can someone confirm that this is the correct connection for the hose?
