Here is the thread that I started about exactly a year ago, and it appears that it was probably a rolling change in 1992 - some models, like the 400E's, 500E's, and at least the diesels got R134a.

300E's didn't get it until MY1993, or so it appears...

http://www.peachparts.com/shopforum/showthread.php?threadid=41313&highlight=new+refrigerant

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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".