Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Dieseling on 1985 MB 300CD

Engine continues to run at idle when switched off with key. Engine stops only after pressing Engine Stop button under hood.

1. What are possible causes/solutions?

2. Could a remote button inside car be rigged to actuate Engine Stop button under hood?

When you turn off the key, a “stop engine solenoid” is supposed to perform the same function. Not a major repair on these cars, any Benz shop can do it without breaking the bank…

The shutoff is vacuum operated (No Solenoids!)and can be caused by something as cheap as a vacuum line knocked off. If the oil filter has been recently changed that is the likely culprit. The oil filter is mounted on the firewall drivers side. Look there for any vacuum lines off. Otherwise it’s leaky valve in the vacuum pump. Cheap and easy DIY repair.