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65 with factory air the lines get cold but its not transferring the cold, I took the car to a AC guy and he checked it out and says there is probably a door or damper problem inside the duct work. How hard is it to check this out. Would I take the glove box out to see if I can see a problem from there.
65 with factory air the lines get cold but its not transferring the cold, I took the car to a AC guy and he checked it out and says there is probably a door or damper problem inside the duct work. How hard is it to check this out. Would I take the glove box out to see if I can see a problem from there.
I would first check to make certain that the hot water valve on the inlet to the heater box is CLOSED. Valve is located under the hood on the passenger side near the rear of the engine. It has a attached vacuum line. Valve is/should be closed when no vacuum is present on the vacuum hose.
The next step is observing the levers on top of the heater box from inside the car under the glove box to make certain they move when you pull/push the AC console *****. It is possible that some of the internal insulation strips have fallen off from age and are blocking the doors from opening and closing. The Chevrolet Service Manual on AC has excellent drawings and troubleshooting information. That way you can read and see what the inside of the heater and AC boxes look like and where these doors are.
Larry
Last edited by Powershift; Jul 26, 2018 at 01:28 PM.
Thanks Larry, I actually changed the hot water valve just to make sure I will check into your other suggestions.
Thanks again
Ron
Be sure you install the correct valve..........that is closed with no vacuum, and requires vacuum to open. There are very similar valves being sold that operate just the reverse These were for the later C3 cars. So double check what you have to be sure.
The Chassis Service Manual has an excellent diagram and explanation of how the various doors work separately and together in the GM Re-Heat A/C system in your Corvette. Between these diagrams and the explanation of the function of the A/C control ***** in your owner's manual, this can help you understand how the "blend" system works (and what makes it NOT work).
Yes that's correct good air flow but not cold and you can feel that the lines are cold under the hood
Well then, if the air is coming out of the A/C vents when A/C **** pulled and fan on high I think you might be barking up the wrong tree. What lines do you say are cold under the hood? I'm thinking you may have a bad or plugged expansion valve, the orifice is very small. The damper doors in this system are all mechanical. If you can select heat and defrost and both work correctly at high speed - and pull A/C on - fan high speed and the air discharges from its proper vents in proper quantity I think the trouble is an evaporator that isn't doing any evaporating. Have you had gauges on this system to observe high and low side pressures?
I had it to a AC guy and he told me the pressures were good, so I don't know. I think I need to find someone familiar with C2 AC systems. Thanks for the info
I agree with all of those above that have directed you to stop the HOT water from entering the heater core. I would remove the heater hoses at the fire wall and either plug the ends or get a nipple that will allow you to connect the two ends together and run your system and enjoy the cold air. Many years ago, I had the same experience as you, a working system and no cold air. I took my 67 to a local Chevy dealer and watched as the service man checked my system. All pressures were OK, the compressor, evaporator and all ac valves were working within spk. No cold air. The dealer was no help.
I returned home and got out the service book and found out about the vacuum controlled water shutoff valve. I removed the vacuum line that was attached to that valve and plugged it with a nail. Started the car and the cold air was wonderful. The hot water that was being supplied to the heater core was killing the cold air.
Ac
