The 111 cap is metal with a thin ridge down the center. I believe the 102 cap is the original one on the 102/103 engines with a thin ridge (made of plastic). I don't think you can get a gasket for the new ones, but they only cost a couple bucks. You'd have to remove the gasket and measure it to see if it is the one with a 38.5mm hole in the center.

They all fit the same.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!