Air conditioning mystery

7 times to the mechanic. He replaced the compressor, drier twice, sucked dry 3 times. Will warm up to 62 at stop, slowly, 20 minutes, drops to 42 while driving, on a hot day. Works well and drops to 40 on a cool day. Sponge pieces come out of vents. Mechanic says mixing door seal, $600, so I put a vice grip on the heater hose, no effect. I think maybe radiator fan? It seemed fixed for a week after replacing the expansion valve, then bad again.

. Mechanic says mixing door seal, $600, so I put a vice grip on the heater hose, no effect.

Well I’m not surprised. Did you expect a vice grip on a heater hose would fix a mix door seal?

I might suggest a second opinion by a A/C expert. Often they can be found at local radiator shops.

I second Joseph’s post. Any good AC shop should be able to fix it. It sounds like the expansion valve may be bad, or perhaps there’s an uncorrected leak.

I suspect you were trying to stop hot coolant flow through the heater core with the clamp, but I don;t think that’s the solution.

The mechanic said the vent seal was allowing warm air from the heater core to mix with the cold air. If the hose is pinched, the heater core should not heat up. There is no air access from outside through the heater box. I’ve been to four other shops, who all object to the vent door reason. They said: the new compressor defective, expansion valve, drier, drier.