They leak, causing the loss of freon (r134a).

The evaporator is much more accesible on W126s, but on W124's, book time is about 16 hours.

The evaporator's themselves are not terrible expensive, but 16 hours of shop labor is not pretty.

If you are a competent DIY'er, you can do it in a weekend, as many on this site have. It's just a matter of disassembling the dash to access the evaporator.

BTW 1992 400E / 500Es and all 1993 and newer MB's come from the factory with the new R134a refrigerant.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".