When it is hot outside (over 100 degrees) and my car sits in the heat after driving it, upon restarting, the a/c compressor will occasionally not engage. It will engage, however, after shutting the engine off and restarting it.

I talked to my tech and he said that it is a fairly common problem in hot climates. He said a heat-soaked car can cause just enough excessive a/c head pressure at the start up to lock out the a/c clutch. Then, when it is restarted, it will work okay. Mine leaves the a/c lockout code afterwards.

I'm not sure if it's the high back pressure causing the belt to slip or maybe it's the overpressure switch. I thought about trying a new belt or maybe replacing the tensioner. Has anyone dealt with this?

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1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles