Brcmpbl

1970 L46 with factory AC.

Here's one for you: my heater was not blowing warm air, and the heater control valve was looking pretty ugly. My AC blew cold.

So, I replaced the heater control valve with the correct one and my heater now works just fine. The issue is, I've now lost my cold AC (seems to just blow ambient temp). Anyone encounter this before / any insights? Thanks.

AzMotorhead

Do all the deflector doors operate correctly? Does the AC compressor engage? does the heater valve close when heat is deselected?
Looking to see if vacuum line is disconnected. or if something else inadvertently knocked loose

toobroketoretire

When you put your A/C on MAX vacuum is sent to the top of the heater control valve which shuts off the hot water flowing thru your heater core. So it sounds like you forgot to re-connect the little hose to the top of your new valve. In the NORM position hot water is allowed to flow thru the heater core so you can "blend" warm air with the COLD air and end up with COOL air. So check that little hose...............

Brcmpbl

Hi guys: I checked the vacuum hose just now, and I did have it hooked back up properly. It's on the tube at the top of the valve and is snug. The hose is in good shape.

The compressor and everything engages as it should, and the air diverts to the upper centre dash vents as well. It just doesn't get cold anymore in the MAX position.

Is there anything else I could have knocked off? Maybe the other end of the vac line that connects to the control (though I didn't pull on the hose or anything, so not sure how I could have done that)? Thanks.

AzMotorhead

Can you verify the valve opens and closes when you select a/c /heat.

Brcmpbl

What's the best way to test for this? Thanks.

AzMotorhead

Id say feel the hoses but sometimes that's tough to discern. Get a pair of hose pinch off pliers and pinch off the heater hose coming from the intake. That is the heater supply hose.
Easy way to remember which way water flows is remember that "water pumps suck" Every hose going to the water pump is a suction hose.
Also with the ac engaged feel the temp of the line(hard line going into the evaporator does it feel cold ? or is water condensing on the outside of the pipe? That will tell you if the system is providing Freon to cool.

0Willcox Corvette

This will help you identify which hose controls what:

Darinm

Not to hijack this thread, but what is the semi clear rubber part in the upper right 2 pictures called ? It's the part that connects the vacuum lines to the control assembly. I think that may be the source of my vacuum leak and wondering since it seems to be a bit stiff, is there anything i can use to help seal it up or even replace it ?
Thanks

Alan 71

Hi D,
I believe that is often referred to as the vacuum manifold for the rotary switch.
Willcox may be able to advise you on sealing it up or the availability of replacements.
Regards,
Alan