I have a 1984 300D turbo diesel and I am having trouble with it starting in the cold weather. My glow plug light in the dash is no longer lighting up. My question is, is there a controller of some kind that powers the glow plugs?? I dont think that the glow plugs go out all at once or do they??So I am hesitant to replace them at this time. Once the car is started it runs great. I have to keep it plugged in all the time now, and it will start most times but not all. Our temps here in Wa state are around 30F to 55F. I have checked the fuses and they are all good. any ideas thanks

 

I'm not a mechanic, so don't rush out and buy stuff, but I would suspect the problem is the glowplugs. It's happened frequently here lately.

 

I had the same problem on my 1982 300D T. It was a bad relay. The relay is located under the hood in a small black box on the drivers side, inner fender.

 

Hey dude. Sounds like one or more of your glow plugs are bad. What year is the car? Have the glow plugs ever been replaced. There is a glow plug relay that you can check to see if one or more is bad depending on the ohms resistance level.Let me know if you need more help.

Dave

 

check this thread too with the problems and solution for my 300D

https://mercedesforum.com/m_11606/tm.htm

 

i threw 5 new glow plugs in my diesel, and its good for 0 degree starts. jus thought i'd let ya know what it should be able to do.

 

What brand plugs did you put in?

 

to be honest, i have no clue.. i ordered them from napa..

 

you are going to wanto put in the upgraded Pencil syle plugs. generally they are made by bosch. The other kind (loop style) is outdated, in efficient and has other problems. if you have the loop stlyle in your car you will have to remove the groundwire from the last plug when you put the new pencil style plugs in.

let me know how it goes. my car too is having problems starting. Also, might I warn you that replacing the plugs is very difficult because they are generally on so tight and they can be tough to get to with a 12mm wrench. there is not enough room for most ratchets, and with each wrench crank you can only go about an inch. it can be rather frusterating.

good luck