C41988

Hello. I recently got a 1988 corvette. Runs and drives smoothly. I had an air conditioning malfunction though and has been going on since I had it. Whenever i turn on the AC, it usually starts cold, but whenever I make a tight turn, it begins blowing hot. Sometimes when I turn on the AC it can be hot. Also randomly when driving, rarely, it’ll randomly go from cold to hot. Compressor works normally and kicks on, I checked the blend door actuator and it seems to be working as well. Recently did a retrofit to r134a and fixed an o ring leak, so it isn’t low on Freon either. Any advice? Desperate for help during this hot summer. Idk if this will help, but during the winter the heater also struggled to work much, but I don’t remember the specifics, just that it didn’t kick on much. Also when the AC blows hot , the compressor is still running so I’m not sure it’s a compressor issue or not. Help needed

OneRedVette

Auto air? If so, check what the computer thinks the ambient temperature is, especially when the air blows hot.

Also, I don't remember if the 1988s have a heater core control valve or not, but it might be a good idea to poke around and see if there is one.

C41988

Yes auto air climate control. The ambient temperature is accurate (96 but feels like 102) and fluctuates normally. Even when it begins blowing hot it stays normal, when I got home I turned on the AC and it was blowing hot and slowly cooled but not very cold. I am not sure about heater control valve in a 1988 either.

OneRedVette

Freezing coils or clogged evap drain?

My c4 dumps water from the evap drain when running in the summer

C41988

I don’t think freezing coils, and where is the evaporator drain located at in a c4? Sorry I am not an expert at air conditioning in cars

OneRedVette

Its under the car near the blower motor. With the AC running, you should be able to find it very easily.

C41988

Hm. I cannot seem to find anything, theres no dripping under the car near the blower motor at all. Just near the main components like the accumulator which condensates and drips water

OneRedVette

From a really old thread:

"On my car the drain is above the fuel filter. If you look at the evap housing the drain is on the engine side. There is about a one inch thin rubber tube sticking down out of the housing on the bottom. If you crack open the top of the housing and pour water in, you can test it that way. I found that pouring water in other places made a large pool of it under the blower motor."

C41988

this is the only tube like thing I could find under the Vette. Is this it? Above the fuel filter there is no tube or opening in sight.
this does look like it is connected to some other reservoir though.. please lmk I’m not sure

OneRedVette

Again, I'm not certain.
Did you run the ac while looking? It should be extremely obvious while running.

C41988

I found the evap drain. It’s a small hole instead of a tube above the fuel filter, and yes, it was pouring a bit while the AC is running, so it is not either of those

64Scout

You said the blend door motor is working, but have you removed the fan resistor and looked at the blend door itself? It sounds like the rod is detached, and that's why it goes from cold to hot when you make a tight turn.

C41988

I just took a quick look at it and moved some wires aside and checked the blend door motor out. It looks like there’s nothing attached

looks like a little white nub attached to nothing. What do I do from this point on?