Technoholic
Active Member
You could just fit the modified seal with a normal jubilee clip to the old pcv pipe if your pcv valve is ok, like I think mine is, but still need to buy the old complete assembly to get the seal in the first place.
OM642 CLS 350 Turbo oil seal?
- Thread starter Technoholic
- Start date
MrGreedy
MB Enthusiast
Definitely an option. Even if I had the new PCV, I wouldn't know how to fit it. It looks like the whole engine needs to be tipped to gain access. Double pain!
Technoholic
Active Member
I just whipped off the y piece to have a good look. Firstly the pcv seal has no ribs on it at all, definitely worn, and the inlet seal has a big ridge inside it, I’m guessing this is a sign of wear too. Doesn’t look massively oily underneath but there has definitely been oil there.
Secondly, the pcv valve on my car actually seems like it’s just about accessible enough to get a socket on the 2 bolts, there is enough gap at the back of the engine to work on it, although it will be hard. I don’t know if the E class is slightly different to my CLS in that respect though?
Secondly, the pcv valve on my car actually seems like it’s just about accessible enough to get a socket on the 2 bolts, there is enough gap at the back of the engine to work on it, although it will be hard. I don’t know if the E class is slightly different to my CLS in that respect though?
MrGreedy
MB Enthusiast
I've got some crappy Draper 1/4" and 3/8" sockets that I keep so that if there's a nut or bolt head that's a very tight fit for the socket wrench, I grind the socket down so that it is only as deep as the nut head. This allows more room.
The other option is I need to just stump up for a decent set of ratchet spanners! Wife will be pleased (not). If I buy these on this Friday (14th Feb), that really wouldn't go down well! I already have socket sets, but the best value & quality I can find is the mega Halfords 200 piece (or similar) socket and spanner set when it is on one of the better than half price deals. Mind you, doing this instead of paying someone to do it will basically pay for the tools, and spare socket sets is no real issue, as various pieces seem to walk now and then. Including my 1/2" wrench!
I think if I'm going to do the PCV/seal job, I'd rather fit a whole new pipe and take the seal off another new pipe for the older engine. Might as well do it all properly!
The other option is I need to just stump up for a decent set of ratchet spanners! Wife will be pleased (not). If I buy these on this Friday (14th Feb), that really wouldn't go down well! I already have socket sets, but the best value & quality I can find is the mega Halfords 200 piece (or similar) socket and spanner set when it is on one of the better than half price deals. Mind you, doing this instead of paying someone to do it will basically pay for the tools, and spare socket sets is no real issue, as various pieces seem to walk now and then. Including my 1/2" wrench!
I think if I'm going to do the PCV/seal job, I'd rather fit a whole new pipe and take the seal off another new pipe for the older engine. Might as well do it all properly!
Technoholic
Active Member
Remember the bolt heads are reverse torx not standard hex. I'm going to order the up to date replacement pcv assembly, and fit that, then down the line I will try to get hold of the modified seal, and some oetiker clamps to replace it to be a factory finish. I've also discovered that the air intake oval seal on one side has been ripped apart by incorrect fitting in the past, so they need replacing too
MrGreedy
MB Enthusiast
Thank you, good to also know.
I only buy 6-sided, anti cam (recessed corner point) sockets, and these fit reverse torx perfectly.
Technoholic
Active Member
Right, just popped to MB and bought and fitted new turbo intake seal, pcv hose seal and both air intake seals. 20 minute job. Can’t believe how much tighter the pcv seal is than the old worn one.
I will look into the mod for this hose as time allows but this new seal should be fine for the immediate future.
I will look into the mod for this hose as time allows but this new seal should be fine for the immediate future.
Some very good info in this thread. I bought a 2011 cls 350cdi fairly recently and changed turbo, pcv and the two air intake seals. Looked after a couple of hundred miles and there still seems to be a bit of residue in the area. Suspect green o-ring but before I do that could someone confirm the pcv hose is seated correctly in the seal. See pic taken from under the ‘bat wing.’ Thanks
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You could shove it in a bit more, but it shouldn’t leak like that.
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You need to clean it all down and then see where it starts to build up from, though the green seals do compress with age. If you are changing the green seal then check all of the pipework to the intercooler as there may be others that have gone that would be worth replacing at the same time.
Thanks both, have taken the bat wing off, cleaned everything up and may have found the culprit - looks like turbo seal at the bottom was not seated correctly.
I’ve put it all back together, seating pcv seal correctly too and I’ll check up on it after a hundred miles or so. Based on current use that will be a good few weeks!
I’ve put it all back together, seating pcv seal correctly too and I’ll check up on it after a hundred miles or so. Based on current use that will be a good few weeks!
MrGreedy
MB Enthusiast
A bit of an update:
I've continued to look at this. I ultimately got a 'computer says no' answer from the dealer who allegedly contacted Merc UK.
My findings are:
My engine is 642.852. E350 CDI 265bhp late 2011.
A6420101791 was the original part number on this car, and the ML350 diesel, and the S350 diesel.
A6420102491 is the upgraded PCV/breather hose, with the new integrated orange seal with 'tabs' permanently clipped on to the PCV hose end. This is only updated in EPC for the ML, S-class and possible R class.
I've taken a punt on A6420102491 (£117), and I'm assuming that because the original part was the same across the range of E350 CDI engines of the same designation, that the upgraded part will also fit my E-class. I wasn't able to get anyone at Mercedes to understand the logic that if the original part number was the same, why would the upgraded part number be flowed out across most engines but not the E-class.
I will let you know if it fits. I am expecting it to.
Some pictures to help everyone understand.
This is A6420101791 as you receive it, and is the only option specced by EPC for the E350, but was the originally specced PCV breather across a range of 350 CDI engines.
You will need to push on orange seal A6420940580 to create a seal with the intake just in front of the turbo. Seal A6420940580 is the seal that is known to get sucked into the turbo. Because of its small size, you cannot jubilee clip this on to retain it.
This is A6420101791 with seal A6420940580 fitted. This is the arrangement you can see in Richteo's post (#28) above where he's asking if the pipe is pushed in enough.
This is the modified PCV breather pipe A6420102491 for the ML3530 etc that has a new integrated seal with 'tabs' that is jubiliee clipped on to the PCV hose at manufacture. You cannot buy the orange seal with the tabs on its own like you could with orange seal A6420940580.
I've continued to look at this. I ultimately got a 'computer says no' answer from the dealer who allegedly contacted Merc UK.
My findings are:
My engine is 642.852. E350 CDI 265bhp late 2011.
A6420101791 was the original part number on this car, and the ML350 diesel, and the S350 diesel.
A6420102491 is the upgraded PCV/breather hose, with the new integrated orange seal with 'tabs' permanently clipped on to the PCV hose end. This is only updated in EPC for the ML, S-class and possible R class.
I've taken a punt on A6420102491 (£117), and I'm assuming that because the original part was the same across the range of E350 CDI engines of the same designation, that the upgraded part will also fit my E-class. I wasn't able to get anyone at Mercedes to understand the logic that if the original part number was the same, why would the upgraded part number be flowed out across most engines but not the E-class.
I will let you know if it fits. I am expecting it to.
Some pictures to help everyone understand.
This is A6420101791 as you receive it, and is the only option specced by EPC for the E350, but was the originally specced PCV breather across a range of 350 CDI engines.
You will need to push on orange seal A6420940580 to create a seal with the intake just in front of the turbo. Seal A6420940580 is the seal that is known to get sucked into the turbo. Because of its small size, you cannot jubilee clip this on to retain it.
This is A6420101791 with seal A6420940580 fitted. This is the arrangement you can see in Richteo's post (#28) above where he's asking if the pipe is pushed in enough.
This is the modified PCV breather pipe A6420102491 for the ML3530 etc that has a new integrated seal with 'tabs' that is jubiliee clipped on to the PCV hose at manufacture. You cannot buy the orange seal with the tabs on its own like you could with orange seal A6420940580.
How did this go? Did it fit OK? And did you notice any difference when you removed old one?
MrGreedy
MB Enthusiast
Car in garage today/tomorrow with oil cooler seals. I'll hopefully update this week 
That's a bummer about your oil cooler seals. I thought they were updated in 2010 to the purple type.Car in garage today/tomorrow with oil cooler seals. I'll hopefully update this week
MrGreedy
MB Enthusiast
All now fitted.
I fitted part A6420102491.
A6420102491 is the upgraded PCV/breather hose, with the new integrated orange seal with 'tabs' permanently clipped on to the PCV hose end. This is only updated in EPC for the ML, S-class and possible R class.
The 'upgrade' ONLY relates to the orange seal on the end where it connects to the batwing I believe, and eliminates the risk of the previous 'push on' seal getting sucked into the turbo.
Pictures on this thread:
OM642 PCV Upgrade | Engine
Ah, so I need to replace it with A6420101891? Let's see how much mercedesofnewcastle sells it for
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