Have owned my 2015 ML63 (94k kms / 58k miles) a few months now and I wanted to collect all of the digital service records for the vehicle so I could start planning preventative maintenance etc

The local MB dealer provided copies (personal info redacted) of invoices for repair work completed in the last 2 years, this included the usual Service A/B type stuff and also a trans service, air filters, brake fluid flush.

So not exactly comprehensive, but that's all they were prepared to disclose. I knew there had to be more service work, possibly completed at another dealership(s). I ended up purchasing a digital report online for 30 EUR which included service history from new (at a mixture of MB dealerships), and more interestingly a number of warranty claims (detail provided was very high level).

Two warranty jobs stuck out like sore thumbs. Here is what I found.

Claim damage code description : "Timing chain Torn/cracked"
To extract more precise details on what was actually fixed under warranty I phoned the MB dealer (not my local) to inquire further. To my surprise they were more than happy to email me the full repair document (personal info redacted). The car was three years old at the time and had 31k miles.... CEL was on, engine running rough, compression low, timing was out, cylinder bores inspected and all fine, engine removed from vehicle for further inspection - bank 2 secondary chain "broken/snapped". All chains, tensioners, guides, rails, idler gear replaced under warranty (including a long list of seals/gaskets/bolts/fluids).

I was surprised this car, being a 2015, had this issue - I was under the impression the timing chain stretching was a pre 2013 related problem.

One possible cause for this failure is the previous owner followed the original MB service intervals of 20k kms prior to the warranty claim - from what I've read this is far too long for the M157, I wonder what impact this had on the timing chain suffering damage? Anyway, moving onto the next service history shock....

Claim damage code description : "Crankcase Oil consumption too high"
This occurred the following year at 68k kms / 42k miles. I phoned the SA at my local MB dealer to inquire further and he wasn't prepared to disclose anything about this warranty claim, citing previous owner privacy. After some cyber sleuthing I managed to track down the full details of the claim. It was a sobering read.... CEL appearing intermittently, cylinder bores inspected and found piston ring gaps overlapping causing cylinders to "oil up" resulting in a "scored bore" (unfortunately no mention of which number cylinder this was). Engine removed from vehicle. Engine block replaced (!!) including: new pistons/rings, 1x connecting rod, spark plugs and an enormous list of seals/gaskets/bolts/fluids. Original bearings were not replaced, no damage detected.

Would hate to think how much this type of repair would have cost outside of warranty, significantly more than a second hand engine I suspect.

I'm in two minds whether having basically a bottom end rebuild is a good thing or not, I mean who actually did the rebuild? Was it rebuilt to the same standards and specifications used by the Affalterbach builders? I very much doubt it. I would have preferred a brand new engine rather than the local MB mechanic, who probably spends most of his/her week replacing oil and cabin air filters on Sprinter vans, complete this highly skilled work. Though on the other hand, my crankcase and pistons have a mere 26k km / 16k miles on them.

Oh well, there is nothing I can do about it now (except sell), the car runs like a dream... at the moment. Just concerned what other damage was inflicted on the top end during those extended service intervals. Fortunately since that first big warranty claim (for the timing chain) all oil and filter changes were done at 10k kms (6k miles) or less, but who knows what other damage may have been done during those first few critical years.

 

Good that the engine was replaced, even if it is a rebuild.

M278/M157 are known for cylinder scoring. It's the nature of the beast. Statistics and probability being what they are, there is no way to predict if, or when, your engine will suffer cylinder scoring. Drive it, enjoy it, and consider selling it after a short but intense love affair.

 

I'm holding my breath on the 63. So far so good.

 

Those engines aren't ageing well. In some cases as these cars age and the values decline the repairs are worth more than the car already. Now, the hot V engines are starting to show problems with thermostats and camshaft adjusters, and the repairs are incredibly expensive due to increased labor from the front mounted intercoolers. I wouldn't own any twin turbo Mercedes engines without some type of warranty.