OM651 timing chain @76k miles, to replace or not?

[Bobclive2]

I have a C Class coupe 1.8 cgi M271 engine, I purchased the vehicle with 28,000 miles it is now at 41,000, I disconnected the stop/start system within a few weeks of owning the car purely because I disliked it, When I purchased the car I had no idea at that time there was a timing chain issue . It appears to me by using a system that initiates hundreds of thousands of extra starts on a timing chain and tensioner known to be a weak link within Mercedes engines is utter stupidity. To overcome the moment of inertia there is surely always extra loading on the chain at every start up, worse if the timing chain is not under the correct tension because of a failing or weak tensioner. It is important to find out whether the stop/start system is the cause of the earlier chain failures on the 1.8 cgi 271 engine after 2011.

 

[GeorgeR]

Should last for 100k at least, but typically longer than 200k with all the start stops. (And yes, half of it is plastic.)

 

[Bobclive2]

Should last for 100k at least, but typically longer than 200k with all the start stops.

As stated the timing chain receives its maximum loading when overcoming the moment of inertia, that`s at engine startup. The estimated lifetime starts with stop/start technology in play is approx 600,000 as against 60,000 without. You say the amount of starts have no effect on the timing chains longevity, I say that`s rubbish unless the car has covered mainly motorway miles when the number of starts are at their minimal.

 

[CowleyStJames]

I have a C Class coupe 1.8 cgi M271 engine, I purchased the vehicle with 28,000 miles it is now at 41,000, I disconnected the stop/start system within a few weeks of owning the car purely because I disliked it, When I purchased the car I had no idea at that time there was a timing chain issue . It appears to me by using a system that initiates hundreds of thousands of extra starts on a timing chain and tensioner known to be a weak link within Mercedes engines is utter stupidity. To overcome the moment of inertia there is surely always extra loading on the chain at every start up, worse if the timing chain is not under the correct tension because of a failing or weak tensioner. It is important to find out whether the stop/start system is the cause of the earlier chain failures on the 1.8 cgi 271 engine after 2011.

How did you disconnect the stop/start?

 

[Bobclive2]

With this disconnect you will loose brake hold, that was of no consequence to me, I didn`t know I had it for first 18 months of ownership and didn`t trust it anyway.
There are no issues with this disconnect, car drives as normal, no EML`s and no warnings on dash. An added bonus is the smart charging syatem is also deactivated which means the battery is now always near to fully charged even on mainly short journeys. Read thread below, last page.
With this method the stop/start symbol always stays yellow (off).

ECO Stop

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[Bobclive2]

To add to post above, left pic, sensor on neg clamp of starter battery looks similar to this pic, you have to remove plastic battery cover at rear of engine to get to battery.
Right pic, to undo connector push grey tab out in direction of red arrow, when fully out push end in direction of blue arrow, at same time pull connector apart.

 

[Bobclive2]

Regarding Mercedes timing chain issue, the add below is current in the UK Mercedes forum. The car has done 73,000 miles, at 59,000 miles the car received a new timing chain and adjusters, service history is below. This is early for any engine, the car has auto stop/start. I am still inclined to believe that this system with it`s thousands of extra starts is the prime cause of these early timing chain and adjuster failures.

Summary of History:

27/06/12 - 6,581 miles - Mercedes Chester - Scheduled Service -
04/07/13 - 13,324 miles - Mercedes Chester - Scheduled Service + Brake Fluid Renewal -
17/07/14 - 17,496 miles - Mercedes Ipswich - Scheduled Service -
10/10/15 - 34,058 miles - Mercland Nuneaton - Full Inspection + Service + MOT -
06/07/16 - 42,802 miles - Stewart & Wisbey Mercedes Specialists - Scheduled Service + Pollen Filter + Spark Plugs + Front Brake Pads -
03/10/16 - 45,563 miles - Stewart & Wisbey Mercedes Specialists - MOT -
15/03/17 - 48,750 miles - Premier Tyres - Four New Goodyear Tyres -
06/07/17 - 51,879 miles - Stewart & Wisbey Mercedes Specialists - Scheduled Service + Air Filter -
13/10/17 - 55,485 miles - Stewart & Wisbey Mercedes Specialists - MOT -
16/05/18 - 59,211 miles - Stewart & Wisbey Mercedes Specialists - Scheduled Service + Timing Chain Kit & Camshaft Adjusters -
27/06/18 - 60,536 miles - Stewart & Wisbey Mercedes Specialists - New ABS Sensor -
11/10/18 - 62,603 miles - Stewart & Wisbey Mercedes Specialists - MOT -
15/05/19 - 66.500 miles - Premier Tyres - Four New Goodyear Tyres -
21/05/19 - 66,618 miles - Stewart & Wisbey Mercedes Specialists - Scheduled Service + New Front Brake Discs & Pads + Pollen Filter -
27/11/19 - 72,701 miles - Thurlow Garage - MOT -
73,383 miles - Mercland Nuneaton - Full Inspection + Service + MOT -

The car is in excellent condition throughout.

2011(11) MERCEDES C180 CGI AMG SPORT ESTATE 1.8 PETROL BLUEEFFICIENCY AUTOMATIC

2012 Mercedes-Benz C250 Rattling Noise When Starting

 

[Bobclive2]

Timing chain failures

2012 Mercedes-Benz C250 Engine Problems

 

[sweeper]

I have a Viano with 315,000 miles, original chain, no noises

The Viano has now done 341000miles, still running sweetly, no timing chain noises yet, don't do huge mileages but they're still clocking up steadily, i have never had to replace a timing chain on any car, most of which have done over 100k when i bought them and probably more than 200k when sold, regular oil changes, sympathetic driving when cold (ie a light load revs not too high or too low) I believe are the key here, i am slightly concerned with my Jaguar as they had a known issue with the tensioners and lets face it the tensioners or guides are usualy the issue rather than the chain, worn chains can throw up camshaft/crankshaft correlation problems on some engines without any undue noise.