Om642 oil leak.

Ryan87

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E350 cdi
Hello.
I'm wondering if anybody could help me with an oil leak that I have on my 2010 e350 cdi.
I've had the oil cooler seals done at the end of last year but I've noticed the od drop of oil coming from the front of the undertray.
I took some of the front end off today and found oil behind the radiator fans towards the front of the engine.
Does anybody know what this could be?

Cheers.
Ryan.
 

BlackC55

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Check the air intake pipes. They can leak near the belt area.
Is it engine oil or transmission oil?
 
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Ryan87

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Check the air intake pipes. They can leak near the belt area.
Is it engine oil or transmission oil?
Sorry, forgot to mention the orange turbo Air pipe seals were changed too when they had the car stripped down for the cooler seals.
 

TeddyRuxpin

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Check the PCV / engine block breather. They seem to go after 100k miles, mine had both a slight oil leak as well as a vacuum leak

Edit: you said the front of the engine, sorry, ignore
 
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Ryan87

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Check the PCV / engine block breather. They seem to go after 100k miles, mine had both a slight oil leak as well as a vacuum leak

Edit: you said the front of the engine, sorry, ignore
Where was your vacuum leak? Mine hissales a bit when I shut the engine off.
 

TeddyRuxpin

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The PCV - it both leaked oil, and air (vapours) I couldn't hear any hissing.

As I said, it's right at the back of the OM642, rather than the front, so there won't be any drips from there unless you're parked on a hill.
 
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Ryan87

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Check the PCV / engine block breather. They seem to go after 100k miles, mine had both a slight oil leak as well as a vacuum leak

Edit: you said the front of the engine, sorry, ignore
Where was your vacuum leak? Mine hissales a bit when I shut the engine off.
The PCV - it both leaked oil, and air (vapours) I couldn't hear any hissing.

As I said, it's right at the back of the OM642, rather than the front, so there won't be any drips from there unless you're parked on a hill.
Ah OK I get you.
Thanks.
 

mbmb123

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S350 2012 W221
I've got a front oi leak too.
I suspected the high pressure air pipe, which can contain "oily" air, which is why I changed the PVC.
Maybe it isn't the air pipe.

Did you get yours sorted?
 

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Larkone

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Or is oil mist from the turbo to intercooler pipes - had a mist around various areas at the front of the car - similar area to the pic above, changed the oil seals on the turbo to intercooler pipes, cleaned up the oil and hasn't returned. Car pulls slightly better as well so there was definitely an air leak.

Best thing is to gunk off the oil and wipe down the area so you can properly see where the oil is coming from.
 

mbmb123

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The picture shows the end of the metal air pipe making contact with the black plastic pipe that disappears into more black plastic.
I had the water pump changed last month, I think they disassemble from front to get at the water pump, I'm pretty sure there was no oil leak before.
I'm thinking they haven't put it back properly or damaged seals.

I can see the metal pipe in this diagram: AIR INTAKE MERCEDES S-KLASSE [Car] [CHASSIS] (EUROPA)

But what does it join up to. Is it this? INTAKE MANIFOLD MERCEDES S-KLASSE [Car] [CHASSIS] (EUROPA)

I don't know what seals to order?
 

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Ryan87

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Or is oil mist from the turbo to intercooler pipes - had a mist around various areas at the front of the car - similar area to the pic above, changed the oil seals on the turbo to intercooler pipes, cleaned up the oil and hasn't returned. Car pulls slightly better as well so there was definitely an air leak.

Best thing is to gunk off the oil and wipe down the area so you can properly see where the oil is coming from.
Is this the green seal, my leak looks as if its coming from the same place.
 

mbmb123

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It was a black seal, but pretty much same dimensions as the green seal. I suspect the green seal is just a material more resilient to higher temperatures being near the turbo. When I pulled the air pipe off recently, I didn't have the "proper" black seal yet, so just put on a spare green. It seems to have stopped the leak, and now the proper black seal has arrived I don't think I'll bother putting it on as it doesn't seem significantly different to the green. I don't want to risk breaking the black plastic resonator the metal pipe connects to.
 
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Ryan87

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It was a black seal, but pretty much same dimensions as the green seal. I suspect the green seal is just a material more resilient to higher temperatures being near the turbo. When I pulled the air pipe off recently, I didn't have the "proper" black seal yet, so just put on a spare green. It seems to have stopped the leak, and now the proper black seal has arrived I don't think I'll bother putting it on as it doesn't seem significantly different to the green. I don't want to risk breaking the black plastic resonator the metal pipe connects to.
Thanks for the reply. I'll order a green seal and have a go at it when the weather gets a bit better.
 

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