heater control valve
Drifting
Joined: Feb 2003
Posts: 1,614
Likes: 163
From: Davis CA
If you mean the valve that determines whether hot coolant flows to the inside of the car and through the heater core, then you could bypass it. You would just have heat all the time. If you meant the heater core, because it is leaking, then the answer would be no. You can bypass it so that the hot coolant doesn't enter the inside of the car but then no, or little, heat.
Safety Car
Joined: Jan 2004
Posts: 3,783
Likes: 15
From: Northern California
Is this the part? http://www.ecklers.com/product.asp?p...0&dept_id=1193
You could also, fabricate a manual one using plumbing parts from the hardware store.
You could also, fabricate a manual one using plumbing parts from the hardware store.
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1st Gear
Joined: Dec 2008
Posts: 1
Likes: 0
Need a little help concerning "heater control valve" I am confused.
Heater control valve or heater control valve for engne oil cooler system. Heater will not work and I am trying to figure out what I need. The latter has been discontinued and the former does not seem to be what I want.
HEEPPPPP
FAT DAWG
Heater control valve or heater control valve for engne oil cooler system. Heater will not work and I am trying to figure out what I need. The latter has been discontinued and the former does not seem to be what I want.
HEEPPPPP
FAT DAWG
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
The heater control valve is on the engine side of the firewall where the hoses enter .Can be bypassed or replaced with non Vette one as mentioned
Racer
Joined: May 2000
Posts: 482
Likes: 230
From: San Diego CA
2024 C1 of the Year Finalist - Unmodified
Without the heater control valve, it would seem you would have have hot coolant flowing through the heater at all times. How do you keep it from blowing hot air inside all the time. Guess what I'm saying is, I'm not sure exactly how the blend air doors inside the heater work so it would seem that even when you want AC, you would still have the hot coolant flowing into the system and screwing up things.
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Without the heater control valve, it would seem you would have have hot coolant flowing through the heater at all times. How do you keep it from blowing hot air inside all the time. Guess what I'm saying is, I'm not sure exactly how the blend air doors inside the heater work so it would seem that even when you want AC, you would still have the hot coolant flowing into the system and screwing up things.
2nd Gear
Joined: Mar 2012
Posts: 2
Likes: 1
I read this thread about 2 years ago and it did not help me then. My 84 had a leaky heater control valve. Running heat all the time meant having lukewarm air conditioning, too much hot air in the cabin. So, with heat in an 84 it is all heat or nothing. Replacing the factory $130 valve was not in the budget, and no amount of bypassing solved the problem. I live in the desert where spring days can be 85 degrees and nights can be in the high 30s. I finally solved the problem with Four Seasons part #74800 Heater Control Valve. It costs about $30. It cleaned up the plumbing in the engine compartment quite a bit. The original design was a clusterf@#k. The Four Seasons part mounted right up by the heater core nicely and works exactly as the factory did. If ever I have to find this part number again for future repairs, then here it is.
Four Seasons part # 74800 Heater Control Valve
Four Seasons part # 74800 Heater Control Valve
Burning Brakes
Joined: Nov 2011
Posts: 841
Likes: 1
You're right, in 88 they used an electric diverter door, which I don't like because it keeps hot ant-freeze comming in the car all the time. The valve vacumm line works with the control unit inside the car and opens the valve when the heat is turned on, there are replacement valves that are cheap ($20), the OEM's are expensive and are an elaborate set-up of metal tubes. I know people who have installed a simple ball-valve from the hardware store and just open it in the winter and close it in the summer. I was thinking of doing this, because in my car the A/C has to fight the hot anti-freeze inside the heatercore in the summer. I think a control valve was the better design. There are aftermarket valves that are cable controlled, almost like a ballvalve but you cortrol it from a lever inside the car, it eliminates the need for vacumm and bypasses the dash control for on & off.
Last edited by caddyboy84; Mar 30, 2012 at 10:01 AM.
Cruising
Joined: Jun 2013
Posts: 12
Likes: 0
From: GA
I read this thread about 2 years ago and it did not help me then. My 84 had a leaky heater control valve. Running heat all the time meant having lukewarm air conditioning, too much hot air in the cabin. So, with heat in an 84 it is all heat or nothing. Replacing the factory $130 valve was not in the budget, and no amount of bypassing solved the problem. I live in the desert where spring days can be 85 degrees and nights can be in the high 30s. I finally solved the problem with Four Seasons part #74800 Heater Control Valve. It costs about $30. It cleaned up the plumbing in the engine compartment quite a bit. The original design was a clusterf@#k. The Four Seasons part mounted right up by the heater core nicely and works exactly as the factory did. If ever I have to find this part number again for future repairs, then here it is.
Four Seasons part # 74800 Heater Control Valve
Four Seasons part # 74800 Heater Control Valve
I went this route today on my 1984 Vette. Had to purchase the valve and about 18" of rubber tubing to connect the lower heater core at the firewall to the port of the valve (smaller diameter). The 74800 valve has 4 ports but you only need 3 so you need to plug the other smaller diameter port with a cap and clamp, which you can purchase from an auto store. The large ports on the valve will connect to the existing tubing from the back of the block and the elbow that comes off the hard line in front of the valve.
Last edited by raymos; Dec 22, 2015 at 10:43 AM.
Cruising
Joined: Jun 2013
Posts: 12
Likes: 0
From: GA
https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1
