A drop of oil leaking out every couple of minutes is a quart in 500 miles at 60 mph, more or less. I'd bet your oil consumption will drop dramatically with a new cap or seal.

Cheaper than a quart of oil.

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!