Today’s Zip Corvette technical question is one that many 1968-1982 Corvette owners have asked when their heater system stopped working properly:
How do you change the heater core in an A.C. equipped Corvette?
Answer: 1968-1982 Corvette heater cores typically begin leaking due to a breakdown in materials dropping anti-freeze and coolant on your Corvette’s carpet. This is not a pretty sight. Removal of the heater core takes place from inside your Corvette. First the RH side lower dash pad must be removed, then access can be gained to the inner heater box. Remove all duct work (windshield defrost, floor duct, side ducts, etc.). The main inner heater box is supported to the firewall by 4 to 6 studs, these stud plates are riveted to the inner heater box. By removing the nut on the opposite side of the firewall, the inner box can be removed from the Corvette. The heater core is mounted with straps inside the inner heater box. Once the inner box is removed from the Corvette, the heater core can be replaced and reassembly can begin. At this time it is also a good idea to replace all the seals in your Corvette’s heater & air condition system. Seal kits for 68-77 & 78-82 Corvettes include duct work seals, inner box seals, heater/ac flapper door seals and firewall mount seals for internal and external heater boxes. Replacing these seals not only improves your Corvette’s heater & AC performance, but also eliminates air drafts which are common on all C3 Corvettes.
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I am having a problem with my 1977 Corvette heater A/C. While driving the whole system shuts down leaving me with no a/c and no fan. I have cheked the fuse panel under the dash on the drivers side, looks OK , the 2nd fuse is in an inline holder that feeds the A/C relay. Problem is that I cannot locate the inline fuse and relay. Can you tell me were they are located? Also is there any other item that would cause this type of problem?
Trevor,
Is the A/C clutch cutting off or just the fan? The relay is located on the A/C heat box near the valve cover.
Heat keeps pouring into the cockpit thru the ducts even if the controls are off. What is the fix?
Thank you
Mike
Mike,
Your problem is most likely with your Corvette’s Water Shut Off Valve. Replacing this valve should help with the heat coming into your Corvette’s interior.
I can smell antl freeze inside my car. I have checked the carpet and there is no wet carpet but the car is losing anti freeze. I looked under the car and about where the dash board is anti freeze is leaking from the car. I wonder if this means the heater core is bad.
Edd:
If the antifreeze smell is strong inside the car – and you’re seeing the leak more on the passenger side – then you most likely need to replace the Corvette Heater Core. When that Corvette Part is going bad/ leaking, the fluid usually ends up on the passenger side floor of the vehicle. This is a difficult install, you are going to have to remove a lot of the dash out of the car in order to get the heater core out. GM authorized somewhere around 6 hours for this by a trained mechanic with the proper tools.
Replacing heater core – new is not as thick and I can`t get the right one. The old one is 2.5 inch and new one is 2.0 inch What do we do? Make new straps?
Dan:
What year is your Corvette? Is it equipped with air-condition?