Later engines have steel inserts from the factory. 380 and 420 engines (M116) didn't have them in early versions, and the headbolts could sieze. The threads will come out with the bolt.

Doing the inserts requires a special jig to get the angled bolts correct, so this really isn't a DIY project -- costs about $1500 last I heard.

Shouldn't be a problem on anything after 85.

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!