Ultimate OM642 build (2009 R320L CDI, 7G-Tronic)

Ge2tis

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Right, to recoup the story, here is the copy of my introduction post..

Hello everyone, I'm new to this forum but not new to MB in general...Born and raised in the family of Mercedes lovers that started in the early 90s with W123 and continued through out the years, I am currently the proud owner of 2009 R320L CDI bought in mid September 2017 with obviously OM642 engine and 7G gearbox, 180k miles on the clock, 7 seats, AMG bodykit and updated COMMAND system...basically everything that my humble heart wants...it was a tough choice between GL and R Class and the latter won because it's less boxy, cheaper and much easier to live with (my opinion only so please don't judge me ;) ). Well at least it was like that until about a week ago a strange (at first silent) knocking noise from the engine had its presence and within two miles (took time to find a lay-by) became very obvious that something disastrous has happened. That has been confirmed by a recovery technician too who said that bottom end gave up the ghost.
So back at home and after much consideration whether to sell it or keep it, keeping it became clear, I like it too much. So, I had a few options. Being a keen DIYer myself I could either:
1. buy a second hand engine from some "trusted" supplier, fit all the auxiliaries and hope for the best at the engine only cost of about £1200-£1500;
2. find already reconditioned engine at the cost of about £2500 (that's if mine is serviceable, which probably it isn't); or
3. rip the engine apart, find out what went wrong and if serviceable (luckily), recondition to its glory with additional improvements to all known black spots. If crankshaft and/or engine block are not serviceable, somehow find the required parts and then build it up. My guessing I should stay within £1500-£2000 even if I have to source the non-serviceable parts.
Have a quick guess what my choice was?
Obviously I couldn't miss a chance of getting into the guts of this engine even though I had never done that before to any kind of engine. However I am very very eager. I though it might be a great practice in knowing this beauty even more. Plus I could spend a few quid on tools that my small garage still misses without my wife moaning too much about it..he he..and by "garage" I mean a big shed at the back of the garden that I have no access with a car so it is being dismantled on the driveway..
So, after about four days of intensive stripping I can confirm that connecting rod bearings in cylinder no.5 don't exist at all or are very close to non-existing because I can move the rod on the crankshaft easily with about 2-3mm play..the rest appear to be intact however I haven't removed the crankshaft from the block and can't confirm that. Struggling with one of the chain guide pins that has no treads and retreading is not an option as walls are already very thin...
So far, that's my story...will be updating it as regularly as I can and will definitely need some advise from you for my ultimate diesel V6 build..Stay tuned.. ;)
P.S. adding some pictures to accompany the thread.. IMAG0090.jpg IMAG0128.jpg IMAG0104.jpg IMAG0103.jpg IMAG0102.jpg IMAG0096.jpg IMAG0080.jpg
 

ernieh

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Do you think the previous owner knew there was a problem on its way? OK 180k is a lot of miles, but at 23k per year, it could have been mainly motorway miles, so I wonder if there has been some neglect of servicing or perhaps an oil pump failure.

Hope it turns out for you in the end, but it is a big cost after less than 3 months ownership.

Ernie
 

Wighty

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Wow , what a project , really looking forward to it as a fellow om642 owner . I'm retired so Ive cleared my diary and stuck the kettle on awaiting the next run of pics . Good luck with it
 

malcolm E53 AMG

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Look forward to sharing your journey on this, keep the updates coming

Good luck with it and I’m sure you’ll get some support on here along the way
 
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Ge2tis

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Do you think the previous owner knew there was a problem on its way? OK 180k is a lot of miles, but at 23k per year, it could have been mainly motorway miles, so I wonder if there has been some neglect of servicing or perhaps an oil pump failure.

Hope it turns out for you in the end, but it is a big cost after less than 3 months ownership.

Ernie

Whether the previous owner knew it or not, I will never know, nobody would admit to that in the first place anyway...however this girl has full MB service history, which is why I was more than comfortable buying her and by the looks to it, no service delays or neglect is evident.
On the other hand, when taking the engine apart I noticed that the turbo air outlet o-ring seal (green one) was completely missing (hence a bit of oil leaking around there) indicating that it has been taken apart maybe for the oil cooler seals, and one of the swirl flap arms broken in half some time ago with one of the flaps bent in half like a butterfly....and quite a bit of soot in every possible passage...not blocking completely but reducing the flow greatly...so that's how the FMBSH looks like.. :)
As to oil pump failure or low oil pressure, I never saw any signs of it, no dash light or anything...the only weird thing is that R class has no oil pressure light like most other car do...or is it that all MB car has this "feature" now..maybe someone could enlighten me on this one...
Cost wise, yeah, I am not too happy about that, however on the other hand, I am happy that its happened 30 miles from home and not somewhere hundred miles away with all kids in the back on holiday..
 

robparker

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That does seem premature, my 642 is currently on 263k. But it will all be forgotten about once sorted and running again
 

JBell

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Oil cooler seals are a common problem on the 642, I had mine done, 8 hours labour for 2 £4.50 seals!!!

You could just put a V8 in it ;)
 
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Ge2tis

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Oil cooler seals are a common problem on the 642, I had mine done, 8 hours labour for 2 £4.50 seals!!!

You could just put a V8 in it ;)

Yeah, I know...I am yet to find that out if mine has been done...
If only a diesel V8 was an option..:)
 

JBell

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Yeah, I know...I am yet to find that out if mine has been done...
If only a diesel V8 was an option..:)

The new ones are purple in colour

There is a Diesel V8 in the ML420CDi ;)
 
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Ge2tis

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The new ones are purple in colour

There is a Diesel V8 in the ML420CDi ;)

I know about the colour but cheers anyway..;)
The only problem is not enough space under the bonnet and in all fairness I would probably go with 3.2 I6 if that fitted properly and put a 5 speed auto as well because it's easier and cheaper to look after those..:) moreover electrics would be a real pain as well...so I will stick with what I have..:)
 

JBell

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I like the R Class, may be tempted into one next
 

SL63 Mark

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My concern would be that the bits from the lunched bearing will have found their way round the engine into every tiny oilway. Hopefully it can be cleaned. If that is "all" that is wrong that is a result. Do we know why number three big end failed ? Was there any evidence to go on ? Oil starvation ? What are the other bearings like ? Is the rest of the engine good ? Sorry for so many questions, just thinking aloud.
 
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Ge2tis

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My concern would be that the bits from the lunched bearing will have found their way round the engine into every tiny oilway. Hopefully it can be cleaned. If that is "all" that is wrong that is a result. Do we know why number three big end failed ? Was there any evidence to go on ? Oil starvation ? What are the other bearings like ? Is the rest of the engine good ? Sorry for so many questions, just thinking aloud.

Fingers crossed that is all however will have more news when everything is disassembled..hopefully tomorrow as been working for the last five days straight..
Question: would anyone know a good engine specialist not necessarily close to me (Grimsby) as I don't mind driving who not only could check the parts but also wouldn't mind advising and pointing the right direction...??? Cheers in advance..
 

LostKiwi

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I would imagine any engine rebuilder would be able to help you - there are two in Grimsby. Service engineering and FIMS.
The main thing will be to measure the crank journals for out of round or scoring.
 
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Ge2tis

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I would imagine any engine rebuilder would be able to help you - there are two in Grimsby. Service engineering and FIMS.
The main thing will be to measure the crank journals for out of round or scoring.

Thanks, didn't even know there were any in Grimsby...cool..:)
 

malcolm E53 AMG

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Looking at your photos I’d certainly consider changing the engine mountings if all goes well, at that mileage they will be past their best
 
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Ge2tis

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Looking at your photos I’d certainly consider changing the engine mountings if all goes well, at that mileage they will be past their best

That's one thing of many on my list..thanks ;)
 
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Ge2tis

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Update time:

Alright, managed to get that pin out, removed the heads, oil pump, water pump and left with crankshaft pulley and internals.
Pulley bolt turned out to be a proper headache, couldn't remove it even with brand new Clarke air gun rated at 680NM, so put the flywheel back on and now waiting for the locking tool to arrive, hopefully that will sort it (on the other hand, maybe someone local has that tool and would save me a lot of waiting time as delivery is at best next week and no local shop has one for sale, and MB dealers are not allowed to sell them apparently)
Anyway, skipping this step, started to remove the connecting rods and as suspected it is not good...however by the looks, it is only one so far, all fingers crossed (removed only two from that same bank, didn't touch the rest). Will finish the rest tomorrow.
Pictured attached.
Any advice is greatly appreciated..please share your thoughts.. IMAG0174.jpg IMAG0169.jpg IMAG0168.jpg IMAG0167.jpg IMAG0166.jpg IMAG0165.jpg IMAG0163.jpg
 
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Ge2tis

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More photos.. IMAG0192.jpg IMAG0191.jpg IMAG0188.jpg IMAG0184.jpg IMAG0183.jpg IMAG0178.jpg IMAG0176.jpg
 
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Ge2tis

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More photos... IMAG0201.jpg IMAG0200.jpg IMAG0199.jpg IMAG0198.jpg IMAG0196.jpg IMAG0195.jpg IMAG0194.jpg
 

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