Piston Slap: Hot Air on Frozen A/C Evaporators?
TTAC Commentator Stefan writes:

Sajeev, my old triple-black 1997 Town Car has developed some air conditioning problems and my trusted independent shop seems unable to duplicate it nor to understand it. Maybe you and the B/B can help?

The a/c always works when starting up the car but will abruptly cut out after a while, almost as if the clutch disengaged. This happens even when the system is fully charged. I was told by the technician to keep the fan blowing full speed but this merely delays the inevitable cutting out. There does not seem to be a refrigerant leak. Not being an air conditioning expert by any means, I am at a loss on how to proceed.

The car has only 170,000 miles on the meter and should be good for another 100,000. Not wanting to spend big bucks on replacing the entire system, where to start?

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  • ToolGuy 9 miles a day for 20 years. You didn't drive it, why should I? 😉
  • Brian Uchida Laguna Seca, corkscrew, (drying track off in rental car prior to Superbike test session), at speed - turn 9 big Willow Springs racing a motorcycle,- at greater speed (but riding shotgun) - The Carrousel at Sears Point in a 1981 PA9 Osella 2 litre FIA racer with Eddie Lawson at the wheel! (apologies for not being brief!)
  • Mister It wasn't helped any by the horrible fuel economy for what it was... something like 22mpg city, iirc.
  • Lorenzo I shop for all-season tires that have good wet and dry pavement grip and use them year-round. Nothing works on black ice, and I stopped driving in snow long ago - I'll wait until the streets and highways are plowed, when all-seasons are good enough. After all, I don't live in Canada or deep in the snow zone.
  • FormerFF I’m in Atlanta. The summers go on in April and come off in October. I have a Cayman that stays on summer tires year round and gets driven on winter days when the temperature gets above 45 F and it’s dry, which is usually at least once a week.