This is the 1998 E300 that my younger son currently drives. I bought it in March 2013 from forum member Citationtech, and I noticed the the a/c was weak driving it home from Maryland. I stopped by John VStech’s place in Charlotte on the way home and he charged it up. I was having to top it up constantly.

In July 2014 we had the gathering at the biofuel plant in Winnsboro. John was there and he applied the sealant.
It got better but not perfect. Still had to add a couple cans per summer and it struggled on hot days (of which we have none of those in Columbia, hehe)

Finally in the spring of 2016 I was driving home one night and the compressor seized tight. Tore the whole system down and built it back up again. Evaporator was clearly leaking. Oil stains and green goo in bottom of evaporator box.

Got John to charge it up the weekend after Memorial Day 2016 and I have not had to touch it since.
System has had no problem maintaining vent temps in the 30s no matter the weather since I fixed it.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech