Metallic Rattling OM606 - PeachParts Mercedes-Benz Forum

jake12tech · #1 04-15-2017, 11:37 PM

Advice needed.. I'm getting a metallic rattling from my om606, 1999 with 193k miles.. I replaced the water pump because I replaced the clutch and the fan wasn't spinning as fast it could and right after that I started getting a metallic rattling that sounded like a bad water pump bearing.

Right after the new water pump, the rattling persisted in the same area. So it leads me to believe it's the chain tensioner. This car has been well maintained all its life with oil changes and all. Current oil level is fine.

I'm going to order the tensioner from PelicanParts and see if this fixes the rattle and not drive the car in the mean time...

If my chain tensioner is worn out and rattling, does that mean the chain is worn out most likely as well? I know the only way to check that is by removing the valve cover and aligning the cam and rotating the motor. But i'm interested in the general experiences with these tensioners. But I don't think so for the chain considering it has always had oil changes. Could the oil pump chain be shot???

That belt tensioner shock is new as well that likes to rattle on these motors as of 3k miles ago.

sixto · #2 04-15-2017, 11:55 PM

Is the rattling louder if you idle with the oil filler cap off? I'm not familiar with the vane type vacuum pump but could it be the source of noise? Did you get a quality belt damper or perhaps something like Uro brand? You might recheck the belt tensioner arm bearing and idler pulley bearing. The tensioner arm should pivot smoothly without clicking (detents) and without wobbling whatsoever.

Sixto
83 300SD
98 E320 wagon

Diseasel300 · #3 04-16-2017, 12:46 AM

Is it possible that the tensioner pulley is bad? It's just right there beside the water pump. Sometimes its hard to tell exactly where the noise comes from.

jake12tech · #4 04-16-2017, 12:56 AM

Quote:

Originally Posted by sixto

Is the rattling louder if you idle with the oil filler cap off? I'm not familiar with the vane type vacuum pump but could it be the source of noise? Did you get a quality belt damper or perhaps something like Uro brand? You might recheck the belt tensioner arm bearing and idler pulley bearing. The tensioner arm should pivot smoothly without clicking (detents) and without wobbling whatsoever.

Sixto
83 300SD
98 E320 wagon

Hmm, I don't tink it's the vacuum pump but I didn't try that.. These motors don't typically have these issues. And yup, I only use German parts on my cars. No URO, I read too many bad stories about how bad the quality is for even for like rubber flex discs... It sounds like it's right from the water pump area. But the only thing behind there is the chain tensioner, or should I say nearby that would rattle..

Quote:

Originally Posted by Diseasel300

Is it possible that the tensioner pulley is bad? It's just right there beside the water pump. Sometimes its hard to tell exactly where the noise comes from.

Yes, indeed it is hard to tell. How can I check that?

Diseasel300 · #5 04-16-2017, 01:05 AM

Quote:

Originally Posted by jake12tech

Yes, indeed it is hard to tell. How can I check that?

Take the accessory drive belt off and give it a wiggle, then give it a good spin by hand. If it seems loose/wobbly, isn't smooth when spun, or if it seems to spin excessively easy (freewheels) it's probably due for replacement.

chasinthesun · #6 04-16-2017, 09:23 AM

Start with everything external up frt of the motor first(the easiest items to fix would be bolt on parts) .The vac pumps get alot of wear and are the last to be replaced if stilll in working order.If it is working (happened to me) something still could be in its last gasp .The case I had was the vac pump bearing failed AND the tappet was engaging metal to meatl on the roller , it still made vac .This case was small bearings made its way to the oil pan .Tap noise went up and down with rpms.Fixing it too late would mean the tappet would break sending it into the sproket ending the motor most likely ,that is if the design is similiar to the 617 motor.

jake12tech · #7 04-16-2017, 09:33 AM

Quote:

Originally Posted by chasinthesun

Start with everything external up frt of the motor first(the easiest items to fix would be bolt on parts) .The vac pumps get alot of wear and are the last to be replaced if stilll in working order.If it is working (happened to me) something still could be in its last gasp .The case I had was the vac pump bearing failed AND the tappet was engaging metal to meatl on the roller , it still made vac .This case was small bearings made its way to the oil pan .Tap noise went up and down with rpms.Fixing it too late would mean the tappet would break sending it into the sproket ending the motor most likely ,that is if the design is similiar to the 617 motor.

I will check that... I haven't heard of om606 vacuum pump failure, but there's a first for everything.. I don't truly believe it's chain rattle at 192k myself, but who knows... I don't trust driving it anywhere at the moment. My noise goes away with rpms, but intermittent every few seconds at idle at idle..

ROLLGUY · #8 04-16-2017, 10:31 AM

An easy test for the noise coming from an accessory would be to loosen the tension on the belt and start the engine. The belt will be fine not tight around the pulleys, and none of the accessories will be turning. If the noise is still there, you will know for sure it is not coming from an accessory.

sixto · #9 04-16-2017, 11:36 AM

Remove the belt, fan and shroud and watch the crank pulley damper. It might be working loose or coming apart. On second thought, maybe you don't want to look directly at it with the engine running

Sixto
83 300SD
98 E320 wagon

jake12tech · #10 04-16-2017, 01:30 PM

Quote:

Originally Posted by ROLLGUY

An easy test for the noise coming from an accessory would be to loosen the tension on the belt and start the engine. The belt will be fine not tight around the pulleys, and none of the accessories will be turning. If the noise is still there, you will know for sure it is not coming from an accessory.

I did this procedure just now and the noise got extremely loud and screeched like belt squeal. Does this mean it's an accessory