Yet another OM642 leak (again)

[TeddyRuxpin]

After changing one intercooler hose/seals I thought I might be leak (and problem) free for oh I dunno… a month or two? But no. As soon as I did that, my xenon’s went. Bad luck. Fine. Sorted them.

After driving the car, I am noticing a very faint smell in the cabin. I can notice it by my partner can’t, at least not until I mention it. Same after parking. Haven’t had this for a while.

Perhaps unrelated but I’m also noticing that my intermittent juddering @ 1500rpm on very light acceleration is still there. Was hoping the new hose/seals would fix that. I don’t think they’re leaking anymore but I’ll double check soon.

Anyway, having a nose around the engine bay, I see the following (see video below).

What are your bets on - could it be the green intercooler o-ring, or imho more likely a fuel rail leak? Anyone had a similar thing?

I’ve had a few diesel leaks from the fuel lines (one severe one in this rough area fixed by an indie). My dad’s OM642 had the green intercooler pipe seal go and it was more of a vapour splatter thing rather than pooling. But maybe?

Obviously I need to remove the batwing and get a better video, but if anyone can throw any troubleshooting suggestions, I’m all ears.

As an aside, ever get a feeling that your car no longer loves you back? Still due a gearbox service, brake fluid flush and the purchase and fitting of a bunch of new suspension parts. Oh and an MOT. Maybe I should stop poking around the engine and just drive it until it explodes like my normal friends do?

Ed

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[TeddyRuxpin]

Sorry, meant to be in the ‘Engine’ forum! Mods, please move if that’s ok?

 

[MrGreedy]

I've had a leak from the (damaged?) green o-ring at the top of the aluminium intercooler pipe. It created a fine mess due to oil misting around that general area, and was more wide-spread than that and obvious as soon as the plastic engine cover was removed.

You changed your PCV gizmo/seal not so long ago, yes? (if so, probably rule that out as the source of the oil getting out of the engine).
What about the orange turbo inlet seal? Whip the batwing off and have a look to see if there is a lot of oil in there and could any be getting out?

Also in that area, are there any inlet manifold/EGR/cooler seals or joints?
I've not yet stripped my aluminium turbo pipe off, so I'm not 100% familiar with the engine bits there.

@unclebuck will likely have a very good idea of exactly what joints are in that location given the Herculean effort he's put in on his OM642 this past few weeks.
Can you offer any suggestions UB?

 

[W1ghty]

Maybe diesel fuel leak , or an injector ? Looks a bit high on the right to be much else .
As to the vibration you feel in the car , how overdue is the gearbox service ?
How are the engine mounts, transmission mount ?

 

[Bellow]

What are your bets on - could it be the green intercooler o-ring, or imho more likely a fuel rail leak?

If you are looking for a fuel rail leak, be very very careful.

Hydraulic injection injury

A maintenance fitter died from hydraulic injection injury sustained whilst tensioning the track of a piling rig.

www.hse.gov.uk

 

[Larkone]

Looks like green o ring. But also check the rubber fuel pipes in and out of the fuel filter, mine started to weep under pressure because the inner layer of rubber fractured. Was difficult to see as the fuel only leaked at the cut ends as it squeezed out between the layers of rubber.

 

[unclebuck]

Need the bat wing off, also the turbo shield for a better view.

Could be the fuel filter. Pipes, mine were fooked, found out after its E service and replaced with new from Mercedes along with the clips.

With the bat wing off its easy to check the union nuts for fuel rail leaks. I got blue paper towel and put it around the Union nuts. The blue would go dark the minute it got wet. Luckily mine were OK all done to the correct torque.

Yes you also need to consider the crankshaft breather right angle bracket that the pcv connects to.

With the bat wing off its easier to see in there.

I'm in work until later so I can't do much more until I'm home

 

[unclebuck]

Meant to say that's down by the side of the inlet manifold and oil turret area. So the bat wing off for better pics etc is a must please

 

[TeddyRuxpin]

Thanks for the suggestions all, couldn't do much today as I had a long drive today. Car is getting good MPG, perhaps an increase with the new intercooler hoses/seals, but too early to say.

I will get pics/video with the batwing off ASAP.

The PCV is on the other side of the engine, though? It's in front of the driver on my engine. Funnily enough I've been thinking of changing the crankshaft breather thing that the PCV plugs into as I saw a bit of residue on that too. However, this could be old oil from when I changed the PCV. As far as I recall it's only a £35 part so could be good to change regardless. I've given it a wipe down and will see if any mess re-emerges.

I do already have a spare green o-ring ready to go if needs be, however it doesn't look like the same kind of leak as I saw in my dad's car, a mist/vapour etc.

Re: juddering/gearbox - it isn't over due yet, it's due in Feb/March time. I have the 7G (not plus) which originally had a 'once at 37.5k and never again' service interval. I ignored that and obviously did it again when I got the car. I'll be getting it done in the next few weeks, but I just have a 'hunch' the juddering is more engine based.... but hey what do I know.

 

[MrGreedy]

The PCV is on the other side of the engine, though? It's in front of the driver on my engine.

I was just thinking what could cause visible amounts of oil from inside the engine to get outside.
Worn seals and joints obviously, and if the PCV is letting oil through (for whatever reason) can the oil travel far enough towards and potentially through the turbo to the aluminium pipe then maybe it then comes out of a damaged (green?) seal. You could therefore potentially be looking for more than one 'failure' point.

UB has provided some good advice for starters about what to strip off to have a look. I wish you fine weather for the weekend buddy

 

[TeddyRuxpin]

Thanks! I tried to dip a cotton bud into the fluid to smell it and see if it smells like oil or diesel, but my nasal investigation was inconclusive. Didn't really have a strong smell

I'm happy to change the PCV breather 'thingy' for good measure in any case! I'll call MB Cardiff tomorrow and see if they have one in stock.

I'd be happy if it were the green o-ring as I know how to deal with that now, not a big deal. But I have a feeling it's fuel related - the fuel rail system is something I'm completely ignorant of, and a bit scared of too. I had a diesel leak in a similar place when the car was newer to me and I knew a lot less than now (which is funny as I still know nothing!) and took it to an indie - they said they 'tightened' either a fuel hose or line, as it was a bit loose. I can't remember exactly what, but I don't see any hoses around there, just metal fuel lines and the fuel rail. But it's something I should probably learn about. Would the fuel rail nuts be torqued using one of these: Torque spanner

I don't think it will be the fuel filter as I'm not sure how the fuel would get from the centre of the V to that part, it would have to get over a crest, if you get what I mean.

Anyway, more pics tomorrow hopefully!

 

[TeddyRuxpin]

Thanks for moving to Engine forum, mods

 

[Riva811]

OM642 is t he shittiest engine to come out of MB, miss one service cycle and its a gonner.

 

[E55BOF]

OM642 is t he shittiest engine to come out of MB, miss one service cycle and its a gonner.

Funny how they've sold hundreds of thousands of their shittiest engine, in a score of models, including premium rubbish like the S-class and CLS, and in Dodge, Jeep and Chrysler models too, isn't it ....

OP, if you can't detect much smell, I'm inclined to think it's more likely to be oil than fuel; I find diesel fuel is quite whiffy, and oil generally isn't.

 

[Smiley]

OM642 is t he shittiest engine to come out of MB, miss one service cycle and its a gonner.

The 642 may have a few common issues but it also has good attributes; there are much worse MB engines imho

 

[TeddyRuxpin]

I honestly think that one of the main problems is the oil cooler leak. Not just because of the issue directly, but you know how it goes - take something apart, it never quite goes back together properly! It's such an invasive job.

MB have serviced the car all its life, and they also did the oil cooler & seals on my car and quite honestly the work out of there has been so shocking, I wouldn't be surprised if they managed to balls everything up on reassembly. From my experience, I expect nothing but incompetence from them. As the seals can fail when over 100k miles, who knows how many bits they re-used when they should have swapped them out....

Anyway, I'll keep an eye on things but might not get a chance to take the batwing off for a while due to life issues, so I hope it holds up okay.

 

[TeddyRuxpin]

Another video here with the batwing off. Took some pics too that I’ll post but hard to make heads or tails of anything.

I’m currently cleaning it up a bit.

As I have a spare, I’m tempted to change green o-ring for good measure while I’m here… but not sure that’s it

At the end of the video I zoom in on a bolt with some residue under it. I have no idea what it is, but I tightened it a little, wasn’t very tight. Probably unrelated however.

No idea how to tighten or check torque on those fuel rail bolts… and I’m scared of them.

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[TeddyRuxpin]

Please excuse the photo dump… not really sure what I’m actually taking pictures of! Hopefully someone more experienced than me can clean something useful from them.

Having a coffee then will probably have a go at the green o-ring. Not really convinced it's that, though?

I do remember that when I changed it last time, it was a pain to get it to go in - when it ‘popped’ in and had a good ‘it’s in’ feeling, the bolt on the intercooler pipe wouldn’t line up as it would be too far towards the turbo. So I had to just push it in enough to line it up and leave it be. The intercooler bolt weld is actually cracked a bit. I might change the whole pipe in the future.

 

[TeddyRuxpin]

Part of me wonders if it's as 'simple' as oil from the main turbo seal (which I change regularly), which finds its way UNDER the intercooler pipe, and into that valley? But why would it only go to the LEFT of the engine (or right if you're facing the car), and not to the right/all over also?

I'm going to clean up the area best I can and put a new turbo seal on, as well as make sure that I really tighten up that turbo seal a lot. I'm always a bit scared of breaking the batwing, although the bit that takes the 'nipple' in the orange turbo seal is already cracked top and bottom. Thanks MB.

I might just clean everything up, change the main turbo seal, make sure it's on really tight, and monitor the situation.

It could also be oil coming out of the bottom of the intercooler pipe, though, of course.

 

[unclebuck]

Thats better I can see things now.

ok to do list

replace camshaft breather end casting as myself and @W1ghty did recently, also the pcv valve/pipe if you havent already done so, the big orange seal on the bat wing, change it out for new.
Dont over tighten it as it will crack the plastic more.

When you put the new turbo seal in before you push the batwing back up do it up slightly so that when you slide it on it cant force the plastic back and break it.

other option.

Get everything together and I can pop down to cardiff and help you fit and check things out.