We have a 91 civic whose air conditioner doesn’t work. The coolant level is good, and the compressor is running, but we only get external air coming through the vent. Any suggestions, as long as they’re cheap!
Cheap? Well, you could do a visual inspection to make sure the necessary fans in the engine compartment and the blower fan in the passenger compartment is working. And maybe poke around under the dash with a flashlight and mirror to see if any of the vent doors are hanging up.
Sorry, but to fix this you’re going to need an automotive A/C shop. It takes specialized equipment and knowledge, and in a '91 probably some parts, to get an A/C system working again.
The only cheap alternative is what we used when I was young: “4-40” air conditioning. Open all 4 widows and go 40mph.
The A/C system uses refrigerant; not coolant. Who and how was the refrigerant level determined to be good?
A/C diagnosis generally requires that the low and high side pressures be known. The return line from the evaporator to the compressor should be cold to the touch if the compressor is running and system pressures are acceptable.
If the compressor is running and the line is not cold then there’s a pressure problem.
What do you mean by “coolant level is good”? I assume you mean Freon or R134 refrigerant? And by stating that the level is good do you mean that the operating pressures are good?