Excuse me for also being completely new to this stuff — I’m trying to learn.I recently purchased a 300SD with a little over 300,000 miles on it. It runs really well when it’s warmed up, but even with the summer heat I’m having trouble starting it right up if I haven’t driven it in 6+ hours. It turns over for a while the first try and when it eventually starts, it bumps around before turning back off. It takes me about 3 tries before it starts, and then it’s a little bumpy for the first 15 seconds before I shift into drive. It’s also leaking some baseball-sized oil spots, though I understand that this is characteristic and was assured so by a few people. Apparently the glow plugs were replaced within the 6 months before I purchased it as well. Any clue as to what might be the issue?
‘79 300SD Can Be Hard To Start…
I recently purchased a 300SD with a little over 300,000 miles on it. It runs really well when it’s warmed up, but even with the summer heat I’m having trouble starting it right up if I haven’t driven it in 6+ hours. It turns over for a while the first try and when it eventually starts, it bumps around before turning back off. It takes me about 3 tries before it starts, and then it’s a little bumpy for the first 15 seconds before I shift into drive. It’s also leaking some baseball-sized oil spots, though I understand that this is characteristic and was assured so by a few people. Apparently the glow plugs were replaced within the 6 months before I purchased it as well. Any clue as to what might be the issue?
1 - 5 of 9 Posts
Excuse me for also being completely new to this stuff — I’m trying to learn.
My bad, I’ll get on that! It is a W116, you’re correctWelcome! New is fine. Can I suggest filling out your profile for us please? Complete your Profile
Have you got a W116 or a W126 series 300SD? I think it must be a W116?
Exactly. The first few days after I purchased it, I drove it a good amount and it would start fine the next morning. I shut it down at 9PM one night and didn’t drive it until noon or later the next day and that’s when the trouble started.So it starts fine when warm, and poorly after 6 or more hours, including the next day?
Are you sure the glow plugs are good and are getting powered? Are there any leaks in the fuel system? Anything that lets fuel out or air in will cause hard starting and rough running. Leaky injectors will do the same thing but you won't see any evidence. Check compression and valve clearance, if applicable.
Like I said, I’m really a complete newbie so I’ll probably have to have someone show me how to check the fuel system and compression. I was told that the glow plugs were newly replaced as well as the injectors.
I know this might be a crazy question… but how can I go about checking the two (glow plugs and injectors) on my own? Hahah, thank you
I’ll post some here very soon! Want to give it a nice clean!
1 - 5 of 9 Posts
- This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Mercedes-Benz Forum
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!
Full Forum Listing
Recommended Communities
