I was wondering if anyone knows the year that Mercedes stopped putting plugs into their diesel engines on the 240D model. My girlfriend has a '78 240D, and there is a plug attached to the engine that her mechanic said is used to keep it warm throughout the winter months. Does anyone know more specifics about this feature and if it's on any other models as well? For anyone who is not sure what I'm talking about, it's literally like there is an outlet plug coming out of the engine that she runs an extension cord out to in the winter and keeps plugged in in her driveway when it's not on the road.

 

This is an engine block heater, and gasoline engines use them too. I had a 1996 Ford Windstar that had one, and it was invaluable during the month of February here in PA. In addition to making the engine easier to start in the morning the block heater keeps coolant warm so that the heater begins working almost immediately after the engine is started. Nice.

Some M-B diesel models came with block heaters installed from the factory as standard equipment and some had to be ordered. I think you can get a heater for any M-B model, diesel or gas, from the parts department and install it yourself.

 

Is there a correlation between the glow plugs and the block heater? I'm just beginning to learn about these parts and want to know if there's any older Mercedes diesels that do not require the block heater being plugged in. As I'd mentioned earlier, I have no way to keep my car plugged in, since I live in a city and can not run a cord out of my house.

 

The glowplugs heat the combustion chamber prior to cranking the engine and the block heater heats the coolant. No real correlation other than the fact that they both aid starting the engine in cold weather. If you can't plug the block heater in because of where you live then make sure all of your glowplugs are functioning properly along with the glowplug relay. Lots of references to how to check this pre-ignition system in the M-D Diesel Discussion Forum - use the Search function and you'll find tons of info.