'94 E420, M119 - T-Chain/tensioner/rails Replacement, critical? When must be done?
 

Do the timing chains and tensioners ALWAYS have to be replaced like on the older 420SEL motors (M116?) ?

What is the service interval, if any? I have searched here for hours and have found conflicting information. Some say 100k, some say 150k some say 200k or even that they never need to be changed - only if it gets loud and starts clacking around.

Why all the different advice?

It seems like the failing plastic rails/guides are the big issue. I am surprised people have not advised only to replace the rails, and meerly check the chain at rail//guide replacement.

Do ALL of the tensioners and guide rails need to be replaced?

Looking to buy an E420 and just want to be educated.

Thank you!

There is only 1 MB engine that MB suggested close inspection & replacement of the timing chain..the 1981-83 3.8L V-8 engine.

WHAT MB says on all other cars is to inspect the timing chain for stretch any time the valve cover(s) is removed.

More than 4-5 degrees of stretch on a GAS motor & the chain should be replaced.

And more that 3 degrees on a diesel motor.

YES the tensioner is the MOST common problem that causes the chains to stretch & break. Any plastic rail should be replaced!

All the different advice because of all the different engines. They are not all alike nor are timing chains and tensioners all alike. Plus people have varying appetites for risk. Replacing the lower chain guides is a much bigger job than replacing just the uppers - which can be accessed by just removing the valve covers. I've heard of only one broken 119 lower guide - someone on this forum. I talked to several mechanics who have never seen a broken 119 lower. Curious if Doc has ever seen one. Problems with uppers seem to be much more common.

"MERCEDES BENZ Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
38 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (10 years)"

Now this is a guy I trust!

Thank you Doc!

(and thank you also dean for your advice)

i encourage you to go to the 500e, M119 sites and research this.

many actual owners have replaced them.

it is very expensive to you if it breaks, and they do.

http://www.500ecstasy.com/forums/

Were those the single chain engines?

I have heard some rails or it it tensioners were metal reinforced.
Gosh I wish they would spend the extra few bucks & stop putting crap plastic in a Benz engine...

:eek:

I don't think it possible to do meaningful research at a 500E forum. I have no doubt that some 500E have replaced their timing chains, or had to replace their timing chains. But what would be the relevance? The simple fact is that non-street racers with properly maintained 119 timing chains are not seeing their chains snap.

Yes, Meyle makes them for the M116... but not the M117. :confused: :(

Never again worry about a rail going to break.