Strange Engine noise (video) - Benzworld.org - Mercedes-Benz Discussion Forum

aarons64 · 11-19-2012, 06:47 AM

Hi again, been a while since I've been here. Probably because my w123 has been bullet proof. However, over the past month or so I've seemed to develop a certain rattle or knock type noise. The noise isn't normal present under idle conditions and becomes more apparent under part throttle conditions. It is not a constant noise and seems to get better after the engine has warmed up for 10 minutes or so. To me it sounds like it might be an injector problem, but I want to be sure before spending the money to redo the fuel delivery system. For what its worth last time i changed my glow plugs I found out that I had a severely damaged pre-chamber. Here is a link to thread with picturs of the prechamber. The glow plug tip broke off which led me to pulling it out. Now I did not bother to check the rest of the cylinders but I would think its likely that a fuel problem led to this as well I may have not fixed the root cause of this failure. I will try to post a video of it, but it is rather hard to hear on video. For some reason or another the embeded youtube function isn't working for me So I'm also posting a link

w123 300d engine noise 2.mp4 - YouTube

aarons64 · 11-19-2012, 08:16 AM

Can anyone hear it in the first video?

codepony · 11-19-2012, 11:47 AM

The second video sounds exactly like my 240D, I figured it was supposed to sound like that

I hope someone can help you.

aarons64 · 11-19-2012, 11:57 AM

Quote:

Originally Posted by codepony

The second video sounds exactly like my 240D, I figured it was supposed to sound like that

I hope someone can help you.

The second video is at idle and normal sounding. I was posting it to show that it wasn't making the noise at idle. I just posted it for comparison.

codepony · 11-19-2012, 11:59 AM

Quote:

Originally Posted by aarons64

The second video is at idle and normal sounding. I was posting it to show that it wasn't making the noise at idle. I just posted it for comparison.

Oh good, I was panicking for a bit. It's my first diesel, I'm still getting used to it

aarons64 · 11-21-2012, 07:41 AM

Can anyone else hear the noise in the video?

Rmac58 · 11-21-2012, 08:01 AM

Yes, I hear it.

Adjust the valves and do a compression check.

Pay special attention to the cylinder with the new pre-chamber.

If you can get someone to hold the throttle when it makes that noise, use a stethoscope type of item on each cylinder.

Good luck, keep us posted.

aarons64 · 11-21-2012, 08:12 AM

Quote:

Originally Posted by Rmac58

Yes, I hear it.

Adjust the valves and do a compression check.

Pay special attention to the cylinder with the new pre-chamber.

If you can get someone to hold the throttle when it makes that noise, use a stethoscope type of item on each cylinder.

Good luck, keep us posted.

When I get a compression tester, that's my first step. However, the benz still has lots of power so hopefully that's good news. I think I'm going to pull the injectors and prechambers after that.

Thanks for the reply