I'll just add some clarification to 79Mercy's response. Your 240D has a naturally aspirated engine and cooling down is not necessary. Cooling down periods are critical on turbocharged engines. Letting the engine idle for a short period of time prevents coking of the oil in the turbo bearings.

When I bought my naturally aspirated E300D, I had to relearn my shutdown procedure after driving turbo diesels for over 10 years.

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Nothing cranks me like compression ignition.

- '95 Mercedes E300D "The Great White"
- '98.5 Dodge Cummins 24V 4x4 - "The Green Hammer" (Sold 12-08)
- '81 VW Rabbit diesel w/GTI suspension - "The JackRabbit"
- '00 Triumph Sprint ST for when I need speed