Would you replace either pulley?

[JHZR2]

The top idler one is noisier than the tensioner pulley, but it spins really well. Would you replace it?

What about the tensioner? I cannot tell if the noise is coming from the tensioner bushing or the shock, which is still stiff and functional.

 

[Gokhan]

That is one noisy engine overall.

It sounds like the bushing is what is causing the loud rattle.

OM605 belt tensioner rattle

 

[Trav]

I would say the top pulley is probably out of grease and the tensioner shock appears to be also shot, remove it and check it and replace the pulley.

 

[Kuato]

"Spins well" doesn't mean that there is still enough lubrication in there or that it will last… How many miles on the vehicle?

While you're in there you might as well replace both of them.

 

[JHZR2]

"Spins well" doesn't mean that there is still enough lubrication in there or that it will last… How many miles on the vehicle?

While you're in there you might as well replace both of them.

291k miles...

 

[mk378]

If a pulley makes any sound at all when spinning it by hand, it will be much louder under tension and speed.

 

[JohnnyG]

Top one is dry, I'd replace them both. Figure out what that brown color is on the top one. I'd think rust.

 

[JHZR2]

That is one noisy engine overall.

It sounds like the bushing is what is causing the loud rattle.

OM605 belt tensioner rattle

Its a diesel, It has some other noise sources, and it was stone cold startup at 30 degrees with glow plugs not working.

 

[ls1mike]

I would replace the shock and the pulley. They can't be that much.

 

[OM605]

Old thread i know but was the rattle worse when taking off at around 1000-1200 rpm? I had a shot damper and broken tensioner arm, replaced both with Febi units. It was silent for about a month and now it is rattling like mad again. The rubber bushings at each ends of the damper already looks sad and is separating from the metal. I didn't replace the big 17mm allen. it didn't look worn at all. Also, do those springs lose their tension over time?

 

[JHZR2]

Old thread i know but was the rattle worse when taking off at around 1000-1200 rpm? I had a shot damper and broken tensioner arm, replaced both with Febi units. It was silent for about a month and now it is rattling like mad again. The rubber bushings at each ends of the damper already looks sad and is separating from the metal. I didn't replace the big 17mm allen. it didn't look worn at all. Also, do those springs lose their tension over time?

No. IME on the OM601/2/3 engines, is no, they smooth up nicely just off idle. A little extra oil pressure helps the lifters, and all the rest just runs nice.

Febi stuff is mostly Chinese stuff. Hit or miss at best, short lived generally.

But if you didn’t change the shock with a stabilus, start there. The springs will break, but they’re tuned well enough that any fatigue isn’t really an issue prior to that. It’s really just balancing the action of the shock.

Start with the shock and the alignment of the tensioner and shock/spring, and go from there. The shock should be stiff and smooth along its full range. Often it wears in at one spot and doesn’t really dampen there.

 

[OM605]

But if you didn’t change the shock with a stabilus, start there.

it's a stabilus inside a febi box. I just took everything apart as we speak and i think i found the issue. Here's a picture of the assembly, the small seal is missing, allowing the tensioner arm to slide on the pin, not much but maybe half a millimeter wich is probably enough to cause a rattle.

Edit: Just like the plastic cover on the front of the bolt, the seal is there to prevent dirt front entering the bearing. Obviously the seal was missing and i didn't bother reinstalling the cap on the main bolt which is worn now. Lesson learned.

 

[JHZR2]

it's a stabilus inside a febi box. I just took everything apart as we speak and i think i found the issue. Here's a picture of the assembly, the small seal is missing, allowing the tensioner arm to slide on the pin, not much but maybe half a millimeter wich is probably enough to cause a rattle.View attachment 189387
Edit: Just like the plastic cover on the front of the bolt, the seal is there to prevent dirt front entering the bearing. Obviously the seal was missing and i didn't bother reinstalling the cap on the main bolt which is worn now. Lesson learned.

I’m not sure I’m tracking what small seal you mean. There is a large washer that goes on the tensioner large bolt, without which alignment will be an issue.

 

[Marcozi]

Replace them both with OE parts.

 

[OM605]

I’m not sure I’m tracking what small seal you mean.

Part number 29 (the white seal on the pic i posted earlier). Maybe it wasn't like that on earlier 2 valve engines.

 

[OM605]

Installing a one way alternator pulley seem to cure the wear issues this unit seems to have for some OM60x owners on other forums. I remember someone with an OM606 stating that he couldn't see any oscillation in the belt with such a pulley and that a damper was barely needed.

 

[JHZR2]

Part number 29 (the white seal on the pic i posted earlier). Maybe it wasn't like that on earlier 2 valve engines.
View attachment 189443

Pretty sure the tensioner bearing unit is the same on all of the engines, but the one in your EPC graphic looks different, so it may have changed along the way from 2v to 4V engines, or different timing covers. Note the w126 epc indicates three variants that are interchangeable. Mine doesn’t have the part number for the variant like you show, which is 291 below.

This is from the OM603 in my 1991 350SD, and it’s the same for my OM601 and OM602 cars.

Does the tensioner lever you bought have a 601 part number?

 

[JHZR2]

The new one is an MB part. Right side still has the washer.

 

[OM605]

Interesting. All part numbers start with 606 on mine, including the washer, the cover etcI. I have ordered the whole assembly from the local mb dealer, like shown in the picture in post #12. It is possible to order just the needed parts but i've decided to buy the whole assembly with the arm to be safe.

The bearing looked good but the pin, not so much. I've also ordered a new overruning alternator pulley (it looks like they only sell OAPs for my car model nowadays). This should smooth things out and save the belt and tensioner assembly in the long run.

Here's a pic of the old pin.

 

[JHZR2]

Interesting. All part numbers start with 606 on mine, including the washer, the cover etcI. I have ordered the whole assembly from the local mb dealer, like shown in the picture in post #12. It is possible to order just the needed parts but i've decided to buy the whole assembly with the arm to be safe.

The bearing looked good but the pin, not so much. I've also ordered a new overruning alternator pulley (it looks like they only sell OAPs for my car model nowadays). This should smooth things out and save the belt and tensioner assembly in the long run.

Here's a pic of the old pin.View attachment 189555

Yes the oap is supposed to help a lot if the tensioner chatters. You need a special spline tool to change it.