As part of preventative maintenance on my 1987 190E 16V I plan to replace the timing chain, the top guide rail, and the chain tensioner . This is the most I can do without removing the timing cover, which is a very big job on this car. This means I will not be replacing the tensioner rail or the other two chain rails that can only be replaced by removing the timing cover.

My 190E 16V has approx 156,000 miles on it. I bought the vehicle with 39K miles. The timing chain has always had a very brief rattle on a hot engine start up, especially on a hot Calif day. This has never gotten worse or more pronounced. The chain never makes any other noise. I check the valves every 15K miles and have never seen any visual signs of chain wear. I use Mobil 1 oil changing every 7000-7500 miles.

Question: Is it adequate preventative maintenance to not replace the tensioner rail and the other two rails that require removing the timing cover? I know the rails can break and do major damage, but do I avoid the major risk by replacing the chain, upper guide, and tensioner?

Thank you--Jim Herold

Well I just had my chain tensioner rail fail 2 weeks ago. Very frustrated by the fact that you need to remove half the damn engine to replace it I looked more deeply into the device. Now on mine I never noticed it wearing or brake until it started sounding like a bird under my hood as the chain rubbed the aluminum below the plastic piece. Well when I got the new one I noticed the plastic piece just clips ever so cheaply on the metal portion of the guide. So I devised a plan to make it so I could hold off longer to replace the whole unit. Well it looks like it can be done all from the top with the cam gear removed! So I gave it a shot and even put some nice JB Weld on to make sure it did not move and gave it 24 hours to cure with the tensioner back in place to put pressure on the metal to plastic portion. Well after about a dozen starts and several highway runs all is still solid and probably will last anothe 15K to 30K miles or more before I need to worry again.

Anyway, moral of the story is that if the plastic fails and you can make sure no plastic is in the oil pan or any other portion of the engine it is not an emergency to repair, nor does it require removing half the damn engine. Also your chain slap is most likely the old tensioner, there is a new style that ratchets to tighten so pressure is not lost when the engine is off and therefore tension is still there at start up. Mine was the same way and when I replaced the tensioner all was well! In the not so distant future I am going to do the chain, so during that one I will just remove the timing cover and replace the tensioner arm and the lower guide rail. I already did the top when I did the head gasket.

Just look for wear on that tensioner rail!

__________________
~Jamie
_________________
2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....

Can't say I would feel comfortable driving like that.. I've seen too many bent valves to take Any short cuts in regards to timing chains/tensioners/guide rails..

Just my 2.

Jonathan

__________________
Blue Ridge Mercedes
Jonathan Hodgman
http://www.blueridgemb.com/
Enthusiast Service, Restoration & Tuning.
Follow Us on Facebook!
Located in the Atlanta area
Specializing in all pre and post merger AMG's including Hammers and DOHC M117 engines.
Mercedes Repair Atlanta

Yeah but for a car I paid a whole whopping 800 bucks for and have had for almost 2 years it aint to bad and I was not about to pay some Indy $400 bucks for an $18 part replacement! Some days I need to draw the line. I did not have time and it works perfect. Considering what the old one looked like when it finnaly died I feel this will probably hold up longer than the original did. It is only a very fragile piece of plastic held on with one clip at the bottom and basically slides in the top! Not really a strong design and if the engine runs properly and tension is there it should never ever move! At least it does not now and did not when tensioner before the Weld hardened. It is kind of strange that the part lasts to begin with since it is in constant contact with the chain and has tension on it! Funny how a piece of plastic can last for 18 years and 168,000 miles on an engine that at highway speed runs at 3500 RPM. That is a lot of passes on that little piece of plastic. As soon as I hear chirping it will be done again..... I just decided that ripping it apart was not in my best interests at the time. If it dies then it is time for a new car or a replacement larger motor. I figure this way the wife will allow a 2.6 I6 to be purchased and installed!!!!

And no I do not recommend you do it this way. Although the Indy would not give me a quote for the work since he did not see it and I assume since the Maint CD shows the plastic can be replaced by itself that he would have some trick to get the new one in without removing the timing cover. Of course I also think the MB Engineers were idiots for making a sub $50 part require about a good 5 hours to replace! If only the bolt that holds it came through the timing cover so it could have been removed with less effort and also with the timing cover on! Would have been a nice idea but hey then it would have been too easy for the average Joe to do without needing an MB Tech to do it! Oh well. If she breaks then it is new engine or car time. I have been wanting a 300E anyhow!

__________________
~Jamie
_________________
2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....