Example:



I did not install this one, I removed it to change it. This isn’t the first time I’ve seen a later model filter with that gasket chewed up. Any ideas why it happens?

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (116k)
1991 350SD (206k)
1991 300D (228k)
2008 ML320 CDI (199k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (267k)

Past Diesels:
1983 300D (228K), 1985 300D (233K), 1993 300D 2.5T (338k), 1993 300SD (291k)

Most likely the quality of the seal itself , poor quality rubber.
It’s not been chewed up when filter was fitted it’s the fuel that has eaten away at it , if you look closer it’s almost dissolved.
If you were running wvo or some rough quality biodiesel ie trace amounts of methanol in it then I would blame that as I have seen this on filters over the years on an old w124 I had that I ran on vegetable oil.
So I think poor quality rubber and obviously heat of the fuel has done the damage