Help with heater.
Thread Starter
Cruising
Joined: Aug 2009
Posts: 11
Likes: 0
Help with heater.
Could someone please help me with my '77 heater problem? It will not shut off. I live in Pensacola, FL and the last thing I need is more heat. The A/c does not work either, but that I can live with. I simply would like to kill the heat the easiest way possible. The fan is not on, just hot air coming from the vents. Thank you.
Last edited by Maxriederer; Aug 29, 2009 at 04:15 PM.
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
There should be a vacuum controlled valve in the 5/8" heater hose that shuts off flow to the heater.
The vacuum small plastic tubes can be damaged from heat. Source of vacuum from engine goes in below the hood theft switch into wiper valley. If any of the plastic tubes are damaged, replacing part or most of engine side w/ hose will fix.
The vacuum small plastic tubes can be damaged from heat. Source of vacuum from engine goes in below the hood theft switch into wiper valley. If any of the plastic tubes are damaged, replacing part or most of engine side w/ hose will fix.
Thread Starter
Cruising
Joined: Aug 2009
Posts: 11
Likes: 0
Thank you Ganey,
I will try and sought this out. I may have a few more questions. I sure appreciate you and all those that share their experience and love for these beautiful cars. It has been a dream of mine for a long time to own a Corvette. I now have that car and I will take care of it for as long as I can.
Max
Pensacola
I will try and sought this out. I may have a few more questions. I sure appreciate you and all those that share their experience and love for these beautiful cars. It has been a dream of mine for a long time to own a Corvette. I now have that car and I will take care of it for as long as I can.
Max
Pensacola
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
There are a number of possible failure points for your problem. The water shut-off valve is defective; the vacuum signal line is damaged/blocked/cut; the heater control head has a problem; the heater door servo is damaged/stuck; etc. Anyway, the proper way to diagnose it would be to check for all such failure points, starting with the water valve and working backwards. There could also be more than one cause in the system. 
If you don't really need the heater that much, you can buy a brass water valve for one of the heater lines (Lowe's or other hardware store) and place it on the right inner fender well next to the heater hose bracket. I painted my valve and the hose clamps semi-flat black before installation so that it would be less noticible. Turn lever one way for heat and turn it the other to shut the heat off. 
If you don't really need the heater that much, you can buy a brass water valve for one of the heater lines (Lowe's or other hardware store) and place it on the right inner fender well next to the heater hose bracket. I painted my valve and the hose clamps semi-flat black before installation so that it would be less noticible. Turn lever one way for heat and turn it the other to shut the heat off.
Thread Starter
Cruising
Joined: Aug 2009
Posts: 11
Likes: 0
Thank you all very much. I will have to post a picture of this beauty. The body is almost perfect. Lt. blue with a white pinstripe. I get compliments and looks everytime I take her out. A real eye catcher. I just finished the front and rear suspension. Ran true duel exhaust. I also need to have the frame firmed up. It came form up north, so there is some rust on the rear frame. I suspect road salts. 74-77 were always my favorite body styles. It may not be the most valuable of years, but it's worth everything to me. I've worked hard to buy it. I also graduated high school in '77. I can't explain how I feel when I drive this car. It's got to be that Corvette thing! Thank you all.
Max
Max
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Instructor
Joined: Apr 2009
Posts: 118
Likes: 1
From: baltimore md
had same problem
I had same problem, searched this forum and posted question, people were very nice, someone actually posted pics of how to install the shut off valve from Lowe's .. plumbing section... easy to instal, works great, no more heat coming from lower vents ..
still, there is a problem iI think there should maybe be no air flow, although according to my reading the car was designed to keep air flowing through the interior even though the controls are set to off.
the valve helps a lot but doens't cut off air flow entirely. Just makes it so coolant doens't go into the heater core, thereby hot air is not circulated continually through the interior.
good luck
tk
still, there is a problem iI think there should maybe be no air flow, although according to my reading the car was designed to keep air flowing through the interior even though the controls are set to off.
the valve helps a lot but doens't cut off air flow entirely. Just makes it so coolant doens't go into the heater core, thereby hot air is not circulated continually through the interior.
good luck
tk
Thread Starter
Cruising
Joined: Aug 2009
Posts: 11
Likes: 0
Well, then I guess that would not be a bad thing. As I mentioned earlier, with the tops removed, I don't care about the A/C. I really do not like driving with the tops on. The car looks so much better with the tops removed. The heat is just to much to deal with. We are still hitting 90-92 degrees here. I really will never need the heater at all.
I'm so glad I found this forum. I fell more confident about this process.
Max
I'm so glad I found this forum. I fell more confident about this process.
Max
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
I changed low to off a long time ago.
Blower A/C Vent
Low to Off
There is a 4 wire T connector at resistor connection on A/C evap. box under hood on pass. side forward of the high blower relay & hood spring. Pull connector & bend down the connector to dk. brown wire & reconnect.
Forward speed will push air through the system even w/ blower off on vent.
If someone is running the A/C on low then leave low connected.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Could someone please help me with my '77 heater problem? It will not shut off. I live in Pensacola, FL and the last thing I need is more heat. The A/c does not work either, but that I can live with. I simply would like to kill the heat the easiest way possible. The fan is not on, just hot air coming from the vents. Thank you.
Burning Brakes
Joined: Nov 2006
Posts: 893
Likes: 7
From: Orange Park Florida
I also have a '72. I did not have a factory heater valve, and, the fan runs when the ignition is turned on. I replaced the heater door vacuum valve which stopped the hot air flow into the cabin. I then installed two valves on the heater hoses ( in and out) to eliminated hot water flow through the heater core during the summer. During the summer I routinely open the valves to flush the heater core. Result, no more summer heat problems!
I live in the Atlanta area and cruise the north Georgia and North Carolina mountains so I need heat during the winter. My fix allows heat when I need it.
I live in the Atlanta area and cruise the north Georgia and North Carolina mountains so I need heat during the winter. My fix allows heat when I need it.
Last edited by JimT; Aug 30, 2009 at 11:48 AM.
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
The heater hose connections can be removed from engine & blocked w/ 2 brass plugs from the hardware store. Vac. tube that went to heater valve blocked. No heater hoses or valve.
That's my setup.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
If you have installed the heater shut-off valve in the hose line and still get heat out of the ducting, that is engine heat that is getting into the cabin area. Check to see that the seal/gasket at the rear edge of the hood is actually sealing to the body framework. Often, that seal is worn out/collapsed and the engine heat just blows by it and into the cabin air inlet door at the right side of the wiper/cowl area. Replace that seal and your engine heat will disappear.