OM651 timing chain

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Klanky

New Member
Joined
Oct 16, 2019
Messages
5
Location
Cheshire
Car
C200 CDI
I have a 12 plate 200CDI with 113k on the clock. I've had it from nearly new, ex Merc fleet car, and it has a full MB service history.

A couple of months ago I noticed a slight rattle on starting up. Not every time, and it goes away after a few seconds.

My tame mechanic (ex Merc) says 100% a timing chain problem and that I should replace it asap. He has quoted me £800 + parts [which are not cheap....] and recommended that the chain, tensioner and gears be replaced if I'm going to keep the car. BTW, dealer price for the work is over £2,300 :O

I was going to keep the car another 2 years, but should I get rid asap?
 
I suggest you get a second opinion from MB especially as you usually use them.
As for replacement of the car its up to you. Your car wont depreciate much now and that saving as opposed to a newer car could outweigh repair costs.
 
If you try to sell it and they hear the rattle and know what they are hearing you will get very little for it anyway. If the chain jumps while you are driving it you will get even less..scrap value maybe. I suspect you can get it fixed for less than that. Stop driving it and get it fixed. In 2 years time with stellar mileage on it the cam chain/sprocket change will go a long way to help making it easier to sell. Let us know how you get on :thumb:
 
OM651 timing chain @76k miles, to replace or not?

You need to know in detail what's involved in the two quotes £800/£2300 they may not be the same thing. there are several components potentially involved. sprockets,chain, guides, tensioner. To renew them all in an engine with the timing chain at the rear is an engine out job [ high cost] renewing the chain and tensioner [part] only in situ can be done at lower cost.
Then there's the cars value -market value and value to you personally, how long you intend to keep it, its likely future value as a diesel car, likelyhood of further expensive faults in the future [ rear subframe corrosion appears to be an emerging problem in early cars] before deciding which repair path to take.
Valve Assembly - Mercedes-benz OM 651 Service Manual [Page 18]
 
It's just been in for a service [on a service contract]. The dealer also noted a split bush on the front suspension [strut rod] at £344 fitted allegedly the bust is in unit with the rod. Not had time to check this out yet.

Indie £800 is labour only, and will add on the cost of chain, tensioner, guide and has also suggested renewing the 3 gears if I'm planning to keep the car for the long run. Add on that it will very shortly need new front pads & discs and two new rear tyres and I'm looking at around half the value of the car! There is a couple of other things that I would also want doing, 4 wheel tracking after strut rod replacement for a start, and a couple of scratches that I'd like removed, so maybe time to cut my losses.

Annoyingly, if you ignore the start-up rattle, it's running like a good 'un :( and averages about 55mpg.
 
Added, on line the bushes are about £7 each, so no eed to replace the complete unit which is properly the Control Arm Bush.

Stealers!
 
£344 for replacing one 'strut rod' is laughable £144 more like, less if you DIY (obviously). Owning a car this age and mileage you need to get more creative in sourcing parts and mechanics if you want your bank balance to survive. On my own high mileage C55 AMG I sourced ALL 6 front 'tie rod/control arm' elements , both steering rack ball joint ends, both oil filled engine mounts and Gearbox mount .Complete with new nut and bolt mounting hardware - almost all from Lemforder - for £493..all in

I did the work myself but still, someone asking £344 to replace just one is silly, actually paying that much would be more than silly. Buy the part yourself , any garage can change it for you , it is not specialist work.
 
Inde quoted me £400 Labour + the parts, Those I would only source from MB. Not copy parts. That was for our Petrol 180
 
Inde quoted me £400 Labour + the parts, Those I would only source from MB. Not copy parts. That was for our Petrol 180
Lemforder are not copy parts, they make these parts and supply them to Mercedes Benz, so do Febi Bilstien. Thats what I meant when I suggested you get more creative when finding parts for an old (ish) high mile Mercedes Benz.

Another example while we are here. 245mm vented cross drilled Brembo (OEM) front discs for my V8 AMG...sound - and look - expensive, right ?

£ 131.90..for two..yes 2 , including VAT bought locally, while I was there I bought rears as well (fit when required) £78 for the pair.

Just about everything that moves up and down or goes around and around on most cars is made by a third party company...does anyone on here think MB make their own seats ??? wheels ?? as a result you are able to find them (usually) without buying cheap copies. There are of course exceptions , but for 'run of the mill' cars of a certain age good quality OEM spec parts are readily available.
 
Spot on, although being pedantic Febi aren't OEM. They just re-box. Some parts they sell are Lemforder in a different box and others are cheap rubbish.
 
Thanks for the replies.
Having been through what was needed to put the car into the condition that I wanted was starting to look expensive, timing chain, suspension arm, 4 wheel tracking, 2x new tyres, new front discs and pads and a couple of scratches that some clown put on the bumper touched up it came out at more than 2/3 of what the car was worth.

On this basis, I decided to trade it in before the timing chain became terminal.

I looked at the new C class, but one of my colleagues has had several issues with his new shape C class and, TBH, Inchcape Warrington have been pretty cr4p over the past 18 months. A class is too small, B class a bit "meh" and GLA uninspiring.

I've therefore gone to the dark side and bought a Volvo XC40. I've had Saabs previously so it's something of a return to the Swedish cars. So far very impressed with the Volvo.
 
I have had the same projected fear with the timing chain as Klanky had. It was an OM651 engine in an E class, with 111k mile, mod 2014, serviced all way long. There was some rattling noise just after could start for 5-10 secs.
The quick diag in the workshop (before the 110k service) was:
"Timing chain (system) was going away right now, for sure. Get it changed ASAP."
So they quoted me with a good 800 something + VAT and told me the labour was to be 5 hours and the rest is parts (MB Orig) and they do NOT remove the engine. After the service (regular oil change) the sound went away. So I started to think and the whole story just did not seem to add up.
1.) Could a stretched chain cause any noise with a working tensioner? Youtube videos show 1-1.5 mm stretch as extreme wear. Multiple of this amount should be taken on by the flex of (a working) the tensioner. Isn't it?
2.) Should the chain has 1 mm stretch in it, it needs to cause 1-2 degree deviation in timing. Would it not cause misfiring, power loss and other symptoms as well?
3.) Can anyone replace the tensioner (A651 050 08 00) without removing the complete engine and taking off the two covers and so on?
4.) What is the point to change the two top cog wheels without changing the lower driver sprocket wheel (Drive sprocket / Kettenantriebsrad -> See picture >>>) ?
5.) Is it not the late oil pressure build-up causing a problem which is impacted by the oil change and needs to be handled at the oil pump (sealings) rather than doing anything at the timing chain (system)?

What is your point?


Also did some research on the parts:
I was not able to find any reliable aftermarket parts for timing (Lemförder, Kolbenschmidt, other OEM quality) unfortunatelly. So what is left is MB original:
Chain 220 - 270 (A000 993 82 76 / A000 993 35 02)
Camshaft gear 45-60 (A651 052 0000 times 2)
Tensioner 75 - 100 (A651 050 08 00)
Sliding rails 7-10 each (A651 052 01 00 and A651 050 00 16)
Drive sprocket ??? could not find in any catalogue
Pins for the rails 5-8 each (A137 052 02 74 times 2 and A000 991 52 52)

Means a proper overhaul of timing should cost min 600 as parts (all the above + other sealings, changeable screws etc) + 10+ (maybe 20+) hours of labour.

What do you think?
 
Hi Guys

I had a mettalic rattle on start up for a few months. It was getting steadily worse. I would strat in the morning and it sounded ok for a second and then the rattle would kind of get louder and tappy and then suddenly go after 3 - 5 seconds. It didnt sound good at all.

I took it to MB automotive in loughborough who had the car over night a couple of times to replicate the noise. Which they couldnt as it was intermittent. (Never happened at the garage but always on my drive.. typical)

Anyway long story short I booked it in for the timing chain to be done.

They replaced the chain and the tensioner. Its a single duplex chain on these engines which culd be the issue, others think its execsive use of the start stop.. who knows??

Anyway. The Engine DID NOT COME OUT of the car. The covers were removed, the injectors removed and the rocker cover. The chain is accesible from the top / back of the engine. The mechanic split the chain and attached the new chain to the old one temprarily, rotated the engine by the crank pulley to wind in the new chain. and then connected the new chain together at the top. The tensioner can be accessed from the top also I believ but its very tight.

Anyway new chain and tensioner fitted all seems good. He said the sprockets were in good condition. The chain had stretched very slightly and a few points as he could lift it off the sprockets at certain points in the engine rotation.

My car was on 90K.

I Do think its a weak spot on these, some suffer some dont. He did mention one car with 450K miles on it that they service still n the original chain.... who knows...

He did not mention any need to change any other components.

Hope this helps... The job was done in a day and was not much more than £700 all in...

Cheers
 
The advice I received was from an independent MB specialist who does one of these per week on average, mostly on Sprinter vans. The engine doesn't have to come out, that is correct but a lot of the ancillary components have to be removed. Ditto, my specialist recommended replacement of chain, gears, tensioner, guides and all pins etc with MB OEM as there are no better alternatives available in his opinion.

Yes, it's possible to feed the chain on, but at 100,000 miles it is sensible to replace the gears and complete tensioner mechanism. Obviously, you don't replace the gears by feeding the chain on.

I was quoted £800 labour plus approximately £500 for parts as it's a minimum of 8 hours garage time to do the job properly. MB quote IIRC 8.5 hours at the dealership to do the work.

It's a simplex, that is single row chain, rather than a duplex (two row). Mercedes learned this lesson with the 190 in the late 1980s when they replaced simplex chains with duplex from 1990 onwards. They had obviously forgotten it in the meantime. :(

I note that the new OM654 2.0 diesel is a duplex chain - a tacit admission of a weak spot on the OM651 I feel.

Anyway, I've sold the car and decided to move away from MB. I found the local dealer to be dishonest on the condition of the car when it came to MOT time. Previously they had their MOTs done by an external garage who were fine, but then they started doing it in house and suddenly minor issues became instant fails. Not just my experience either.

Anyway, it's gone and I now have a Volvo instead.
 

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