380sl Chain Rattle with New Tensioner - PeachParts Mercedes-Benz Forum

Build · #1 05-17-2010, 08:30 PM

I installed a new chain tensioner and I still have occasional 1 second startup chain rattle like before. The double row chain and upper guides have only about 20K miles on them.

Ideas? Thanks in advance.

Strife · #2 05-17-2010, 08:32 PM

Where did you get the chain tensioner, and what brand.

Build · #3 05-17-2010, 08:47 PM

It's a Bilstein. I remember what you said before Strife, but I already had it ordered. The old one was a Bilstein which was replaced 20K ago with the other parts. It did fine up until recently.

ironman21 · #4 05-21-2010, 11:41 AM

Quote:

Originally Posted by Build

It's a Bilstein. I remember what you said before Strife, but I already had it ordered. The old one was a Bilstein which was replaced 20K ago with the other parts. It did fine up until recently.

Need to look at the guide rails as well.

Build · #5 05-21-2010, 05:19 PM

I'm going to pull the valve covers and have a look at what's going on. Everything was fine up until recently.

Would a broken guide cause the 1 second chain rattle at startup?

ironman21 · #6 05-22-2010, 02:43 AM

Yes a broken guide would cause a rattle, I am told that both sides upper should be replaced. I understand it is an easy job. I have to do the same on my 560 sl the chain rattles a bit at start but then smooths out. I wish I had more information but until I dig in.

Read this from another great site.

http://www.benzworld.org/forums/r-c107-sl-slc-class/1502838-timing-chain-tensioner-check-88-560sl.html

TMBRichter · #7 05-22-2010, 05:58 PM

A great do it yourself link is Tom Pindelski's, http://www.pindelski.com, it is cheap to gain access to his step by step jobs with pictures on how to do procedures on Mercedes.

He has a great easy to follow procedure on changing the chain rail guides and tensioners. Takes about three to four hours, then cocktails.

Build · #8 05-31-2010, 12:03 PM

I checked and I have no broken guides that I can see, but the chain is very loose on the slack side and I'm not sure how loose it supposed to be?

I'll check to see if the timing is off but I can't imagine it being stretched since the chain, guides, etc only have 20k on them.

Here are some photos. http://www.flickr.com/photos/50705305@N02/4656013039/

http://www.flickr.com/photos/50705305@N02/4656013043/

Build · #9 05-31-2010, 12:43 PM

I turned the cam to check the marks and noticed that the tensioner would easily push back, letting the chain go very loose. I can hear oil pushing out as the chain presses on the tensioner.

I thought it was suppose to hold and apply pressure? Maybe my new tensioner is bad?

Strife · #10 05-31-2010, 02:14 PM

That is NOT normal.

Build · #11 05-31-2010, 02:32 PM

Hey Strife,

The pics aren't normal or the tensioner easily pushing back, or both?

Strife · #12 05-31-2010, 03:11 PM

The oil should not come out of the tensioner very easily. I prefilled mine (the older MB books recommend this) before installation and it was very difficult. I had one of these (Febi?) go bad at 20K , so it is not "incredible" that it would fail early.

Build · #13 05-31-2010, 04:45 PM

I just put a Febi tensioner on it and it's new. The one I removed was a Febi with 20k on it and had started occasional intermittent rattle.

The new one rattles every time I start the car. Is it possible that the seal is bad, or that it needs to be primed? It doesn't leak oil out of the engine, but I guess it could be leaking on the internal passage. If I press a little on the guide rail, it closes completely as I hear it pushing oil out.

Build · #14 06-01-2010, 12:24 AM

Should the chain be as loose as it is in my photo with the tensioner fully engaged?

Would a broken lower guide cause it to be this loose?

Gurunutkins · #15 06-01-2010, 09:14 AM

Hi Build
just a few thoughts
in the second picture you are actually pulling the tension side

remember the crank turns clock wise - the slack should be on the tensioner side ( which is supposed to remove the slack).

there should not be that much slack at any time. No a broken lower guide should not cause that much slack
when you run the engine the tensioner should firm up pretty fast and should over time go a little slack (often takes weeks).

if yours is going flat that fast I would also check the pressure bypass valve in the engine oil gallery (not sure where it is in a 380). it may be stuck open allowing the oil to bleed back really fast and also check the supply to the tensioner valve, is the feed tube open etc.
its definitely not right the way it is
cheers
barri