nelson007

I don't have any heat in my 1967 L-68 with A/C. My radiator is full and I checked the thermostat, all ok.
The two heater hoses do not get hot. Is there a cut off valve in the heater box that would cut off water flow thought the heater core ? I thought the a/c version had a vacuum valve to control the heater water flow.
Any help will be appreciated it's 27 degrees outside.
Thanks,
Nelson007

prestige6

Maybe you have the heater hoses backwards , or a clogged heater core. Or your cables aren't working correctly.

65 Pro Vette

If it original there is a vacuum valve near the A/C box under the hood, controlled by a switch behind the glove box.

Powershift

The heater hot water valve is a fail closed valve………….it requires vacuum to open it for coolant flow and heat.

Pull a vacuum on the tubing to the hot water valve and see if it will open. You can suck on the tubing to get this vacuum. If the valve opens, then the problem is probably the vacuum valve under the dash. It can stick closed or open. It can be rebuilt, or a new reproduction switch can be ordered. LICS has them.

Larry

nelson007

Thanks Larry,
Would you by any chance have a picture of this vacuum valve?

Thanks,
Nelson007

Powershift

How about this one: LICS #35-26B

http://www.parts123.com/parts123/yb....5Z5Z50000370a#

On your car, it should be on the smaller heater hose (5/8 inch) just a few inches from the firewall and heater inlet connections. The vacuum tube to the valve is a very small diameter rubber hose that should point straight down from the top of the valve.

Larry

EDIT: This is the one under the dash on top of the heater box: http://www.parts123.com/parts123/yb....Z5Z5Z50000370a
This vacuum valve supplies the vacuum to the hot water valve in the engine compartment.

Nowhere Man

On the lower heater hose it's a brass valve that's next to firewall/heater box. There are two vacuum lines that goes to it. One goes in though the firewall and to the heater box. The other goes to the intake for the vacuum. When closed it does not allow hot water into the heater core. It's only closed when the AC is on. I would check the vacuum first. And Larry beat me to it

nelson007

Thanks i can see the valve. Where do I check the vacuum ? There is a hose coming from the valve that goes through the firewall.
Thanks





QUOTE=Nowhere Man;1588613168]On the lower heater hose it's a brass valve that's next to firewall/heater box. There are two vacuum lines that goes to it. One goes in though the firewall and to the heater box. The other goes to the intake for the vacuum. When closed it does not allow hot water into the heater core. It's only closed when the AC is on. I would check the vacuum first. And Larry beat me to it[/QUOTE]

nelson007

Keith if i would pull the vacuum hose off the valve and plug it would I than have heat?
Thanks,
Nelson

Powershift

No…………reread post #4.

No vacuum = no heat

Vacuum = heat.

Larry

nelson007

[
Thanks Larry


[/B]