At least here on the "left" coast diesel is $4.50 or more a gallon. Warming up is a complete waste of fuel. If the starting idle is smooth and the oil pressure is normal, drive it gently for the first few miles. The only time one should warm up a car is to clear the glass of fog on a cold winter morning. By nature, diesel fuel contaminates the engine oil, so prolonged idling cold will add more raw diesel to the crankcase.

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81 300CD (sold) 1972 280 SEL 4.5 (sold) 1966 250 S 4 spd (sold) 1974 450 SL (sold) 86 BMW 325ES (sold), 1973 280C (sold) 1988 300 SE.