spankyusmc

What is this piece it is in between the water pump and heater core it is in hose I'm trying to get a pic up. But having trouble Need help with both

MelWff

what year car? which engine? can you describe the part?

BKarol

Always helps .

Does the part just hang there, not attached to the fender, in the heater hose line? probably the water control valve like this: http://www.ecklerscorvette.com/corve...1975-1978.html

Or could be an after market water shut off valve. If it is the one above you don't need to spend the $ on the expensive one. There is another style that works just as well and is cheaper.

Easy Mike

Probably the hot water shut off valve depending on model year. Do you have the assembly instruction manual (AIM)? The AIM will show whether your car had the shut off valve.

spankyusmc

it's an 78 it does look like the pic that karol has . I am shure it is some water control value. But it has vacuum line running in the fire wall .does this control the heater. The heat was all ways on. And I noticed that line running from the part to the fire wall was clasped. And thinking this is the problem why I couldn't shut down the heat

SLVRSHRK

Yes, the HVAC system is all vacuum controlled, and when their is a loss of vacuum, it fails to heat (something about being designed in Detroit I guess )

Sounds like you have some troubleshooting to do.

If the vents are failing to heat (air flow to floor, and the temp is hot), you probably have a significant vacuum leak that is preventing the system from working at all.

If the vents are working and you just have high air temps, it is most likely isolated to the water control valve circuit.

If it is just the water control valve circuit, you can find the vacuum valve that controls vacuum to the valve on the upper side of the interior heater/AC box. The valve is controlled by a cable that comes from the temp slider on your center console and it simply pushes a plunger on the control valve. If you remove the glove box liner, you should be able to see the assembly.

You can test the valve by keeping it depressed and measuring the vacuum (with a gauge) at the valve. It needs vacuum to close the valve, so if you aren't getting vacuum with the plunger depressed, the issue is upstream or you have a bad control valve. You can test the proper functioning of the water valve by using a hand vacuum pump (like the one used to bleed brakes) and applying vacuum to the valve. If the water valve doesn't hold vacuum, or is simply not closing enough, you can replace with another valve. Some folks on the forum put in a ball valve and just control it manually since most of us just drive the car in the summer anyway.

Our systems are old and they deteriorate, so you may have a bad line somewhere.

Just take your time and be logical. You'll find the issue.

allpro2

didn't see an accurate reply thought someone might need the answer in the future. That is how this works right?

vettebuyer6369

Not sure what the post is providing, but its 7 years later.