Odd Grinding Sound on Cold Start-Up 240D - PeachParts Mercedes-Benz Forum

JEBalles · #1 10-22-2009, 06:01 PM

Every now and then, more often now, I hear this kkrrrrr sound when I start the 240 up cold. It happens with the clutch in and out, comes couple seconds after started and lasts about a second. It was happening before but then I think it went away during the summer mostly. That could be because I fixed my idle speed adjust so I start on full idle now. I dare not say the input shaft bearing, that'd be no good at all. Any ideas?

JEBalles · #2 10-22-2009, 08:51 PM

No one?

#3 10-22-2009, 08:53 PM

Just a guess: maybe the starter is hanging up and not disengaging when the engine starts?

jazz · #4 10-22-2009, 09:19 PM

I agree with the starter not disengaging quickly enough. I have been starting my 300D turbo like this for the past 2 years.

JEBalles · #5 10-23-2009, 10:14 PM

If the starter isn't disengaging quickly enough, wouldn't it happen all the time, or at least with the same frequency when warm? It never does it warm. It doesn't mean I'm going to need a new starter soon or anything, right?

#6 10-23-2009, 10:17 PM

I can imagine that it only sticks when it's cold, I'm not sure because I've never had that issue.

Mazootpusher · #7 10-23-2009, 11:02 PM

It will help to take the starter motor out, and degrease and clean the Bendix area,
it could be dirt and gunk holding it a little when disengaging the flywheel.

UriahT · #8 10-24-2009, 09:56 AM

This is a bendix going south.
When cold, the grease in the bendix hardens, and does not efficiently pull the starter away from the flywheel. The grinding is the starter rubbing the flywheel at a different speed than engine idle.
Do it long enough and your flywheel will start losing teeth.
While it may be efficient to replace the bendix itself, rebuilt quality starters are available for not much money. Since you have a 240D, changing the entire starter assembly is much easier than on a turbo car.

leathermang · #9 10-24-2009, 02:32 PM

It is hard to tell for sure which noise it might be.....

but you might want to look in the FSM...

it talks about some noises like that upon startup with a 616.

JEBalles · #10 03-07-2010, 02:13 PM

Alright, I've got a substitute starter in. What should I do with this one? That bendix area (I think that's what I'm looking at) doesn't look dirty.

Stevo · #11 03-07-2010, 02:22 PM

Quote:

Originally Posted by JEBalles

Alright, I've got a substitute starter in. What should I do with this one?

Trade it in on a Bosch rebuild and be done with it.

samboyellowsub · #12 03-07-2010, 04:25 PM

I'm not saying for certain but your chain tensioner spring could be bad. When the oil pressure builds up do you notice the noise simultaneously going away? If so, you need to replace the spring in the tensioner if you're up to it, or the tensioner all together. I had this same problem. When your car is warm it will build oil pressure quickly enough to not make this happen.

JEBalles · #13 03-07-2010, 06:23 PM

Quote:

Originally Posted by samboyellowsub

I'm not saying for certain but your chain tensioner spring could be bad. When the oil pressure builds up do you notice the noise simultaneously going away? If so, you need to replace the spring in the tensioner if you're up to it, or the tensioner all together. I had this same problem. When your car is warm it will build oil pressure quickly enough to not make this happen.

Nope, I switched out the starter about a month or two ago and I haven't heard the sound since. It was also very clear cut, sound, then no sound. It also came after I disengaged the starter by the key, and the sound would come after that, so starter bendix would be consistent.