No heater
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,192
Likes: 111
From: If your not the lead dog the view never changes Boise, Id
No heater
I replaced the heater core on my 1978 put the interior all back together but I still don't get any hot or even warm air thru any of the vents. When moving the switch between defrost, heater, etc it blows out of the right vents. When I move the hot cold switch I can see the cable moving the bracket on top of the housing. I had heads and intake work done and I am getting a feeling they did not put in a thermostat ( engine never getting over 160) but even then I would think that I would at least get warm air.
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,192
Likes: 111
From: If your not the lead dog the view never changes Boise, Id
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,192
Likes: 111
From: If your not the lead dog the view never changes Boise, Id
Ok under the hood I see the valve on the heater hose and a vacuume line connected to it. Where does the other end of that vacuume line go it seems to dissapear near the firewall?
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
That valve receives vacuum when the control is set to max ac and causes the coolant flow to be blocked. Normally the vacuum controlled valve is open to coolant flow with no vacuum signal.
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,192
Likes: 111
From: If your not the lead dog the view never changes Boise, Id
So if I disconnect that vacuume hose and put my thumb to it I should not feel any vacuume unless in max ac, if I do feel vacuume I have something hooked up wrong.
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Racer
Joined: Jun 2012
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From: Winfield West Virginia
2015 C3 of Year Finalist
Did you "burp" the air out of the new heater core? I have seen situations where there was an "air lock" in the replaced heater core that did not allow the coolant to circulate through the heater system. No circulation = no hot air out the vents.
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
That is a possibility but he did not answer the earlier question. Are the heater hoses hot? Before and after the valve.
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,192
Likes: 111
From: If your not the lead dog the view never changes Boise, Id
Plans to work on the car whent out the window today. I will check the vacuume to the valve and see if the heater hoses warm up tomorrow. I have changed out a few heater cores ( not corvette) and I don't think I ever burped one of them. I'm guessing to do that you just disconnect the hose on the output side and run it till coolant bubbles out.
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,192
Likes: 111
From: If your not the lead dog the view never changes Boise, Id
I'm getting a little vacuume to the valve! I disconnected the vacuume line from the valve, let the car warm up and I am now getting warm air in the car. Thank you all for your help. Would it be ok just to leave that vacuume line disconnected for the winter and revisit the problem come summer or would that damage the valve?
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
