Oil leak. M642 again.

[Martyn_n]

Hi,

My car is currently in the main dealer for investigation of an oil leak. 2012 ML350 cdi, 56k miles.
The car drips oil onto the drive and I have had the under-tray off and it is full of dirty oil.
They have rang me to advise that the oil is coming from the seal around the air inlet to the turbo. Now, I do not believe this for a number of reasons; the inlet pipe from the air filters to this o-ring have obviously been changed as they have a manufactured date of 2017, I would expect the gasket to be of similar vintage and in good condition. Secondly I cannot see how this much oil should originate from this gasket as it should only see light vapour through the PCV valve.
Can anybody say whether my suspicions are correct on this or can this gasket indeed produce such a volume of oil?
I am pretty annoyed as this type of seal isn't covered by the approved used warranty so I will be footing the bill for the investigation and replacement gasket. (Also annoyed with myself that I didn't check myself as I would not have charged £58 to replace the part!)

Any insight before I go to pick it up in a couple of hours would be really welcome.

Cheers,
Martyn

 

[W1ghty]

Hi,

My car is currently in the main dealer for investigation of an oil leak. 2012 ML350 cdi, 56k miles.
The car drips oil onto the drive and I have had the under-tray off and it is full of dirty oil.
They have rang me to advise that the oil is coming from the seal around the air inlet to the turbo. Now, I do not believe this for a number of reasons; the inlet pipe from the air filters to this o-ring have obviously been changed as they have a manufactured date of 2017, I would expect the gasket to be of similar vintage and in good condition. Secondly I cannot see how this much oil should originate from this gasket as it should only see light vapour through the PCV valve.
Can anybody say whether my suspicions are correct on this or can this gasket indeed produce such a volume of oil?
I am pretty annoyed as this type of seal isn't covered by the approved used warranty so I will be footing the bill for the investigation and replacement gasket. (Also annoyed with myself that I didn't check myself as I would not have charged £58 to replace the part!)

Any insight before I go to pick it up in a couple of hours would be really welcome.

Cheers,
Martyn

Sounds more like oil cooler seals if it’s filling the undertray ?

 

[Tuercas viejas]

Sounds more like oil cooler seals if it’s filling the undertray ?

Yes I tend to agree .
AND
A comeback in that area after H/E seal repair is not unusual either.
As a footnote cleaning all that sound absorbtion material on belly pans soaked in oil is a chore to come clean, & oil free even with industrial strength detergent & pressure washing before customer hand over .
Tuercas Viejas

 

[KennyN]

I picked up a borescope camera from eBay for around £10 , plugged into a tablet makes a great way to investigate small areas that the eyes cant see or the fingers cant feel.

Pics and video can be taken and used to show the dealer where , or not , the oil is leaking from.

If the undertray is full of oil then there must be a fair amount of the black stuff coming out the turbo and through the seal which should be clear to see and smell , plus any oil that didn`t get out of the seal would be running back into the airboxes saturating the filters.

If the seal is leaking then i would be asking where such a volume of oil could be coming from , a slight mist yes but certainly not enough to soak the undertrays unless your turbo is knackered which should be very / very obvious.

Me thinks the dealer is talking and wanting to save them the work (expense)

K

 

[zipdip]

Well what I find is strange is ok the garage is saying the oil is coming from the turbo,like others on here I doubt there would be very much oil coming from there,so just why the garage is saying this,ok as you say not covered by the warranty,but ok you are having to pay make sure they clean the undertray and then you can check after say a week for oil on the tray then take it back.

 

[Martyn_n]

I have picked it up, and they are in no doubt that I am very sceptical that they have indeed identified to problem. I will keep an eye on it, but as per most people we are not doing much mileage at the moment. I will also do some research as to whether people have successfully claimed under the approved used warranty for oil cooler seals before I drop it into the dealer if there is an ongoing issue, if not an indie can do it.
As it was not covered by the warranty I suppose they did me a favour by not charging me the £168 investigation fee that they could have. Interestingly the receipt shows the gasket, A6420940180, as £2.45 + VAT, which is way below what it should be.

 

[BlackC55]

It is very very very likely that the oil cooler seals are leaking. Oil from that intake pipe will not ever travel that far as to get on the under trays. We do at least one a week btw as its so common.

 

[Martyn_n]

Having looked under the bonnet I have had another thought as to why this may have happened. They serviced the car in October, probably about 1k before the oil started showing. As part of the service this component needed to be removed and refitted to replace the fuel filter, if it was refitted badly / not tightened this could be why they are so adamant they have found the leak. And why they haven't screwed me for as much as they could have.
Does not explain why so much oil was involved though.

 

[Martyn_n]

It is very very very likely that the oil cooler seals are leaking. Oil from that intake pipe will not ever travel that far as to get on the under trays. We do at least one a week btw as its so common.

I am very much swaying that way. Is it likely to get significantly worse quickly? If the warranty will cover it they need to be able to diagnose it by June and I think it needs to be bloody obvious for these guys to diagnose properly.

 

[Martyn_n]

So, the next question is has anyone had the oil cooler seals done under warranty or are the exempt as wear items / consumables?

 

[W1ghty]

So, the next question is has anyone had the oil cooler seals done under warranty or are the exempt as wear items / consumables?

How long have you owned the car buddy , because the leak may have been there a while

 

[mbmb123]

I'm no longer surprised to find badly fitted parts/car trim.
The top turbo seal takes a surprising about of force to seat it properly, at least that was my experience, maybe it wasn't seated.
But, being at the top of the engine I don't see leaking oil getting as far as the under tray, but depends on quantity.

Did you take off the under tray? Where was the oil?
Another oil source is the front of the engine. That large metal pipe running from the turbo to the front has several o ring seals.
Oil can leak from there. The pipe contains not just air but oil vapour from the turbo and probably the crank case vent.

Oil cooler leak. Yep, that's the big one. The 2007 W221 I briefly owned had this issue. Luckily I returned the car.
My current 2012 only has the lesser leaks mentioned. Fingers crossed.

 

[Martyn_n]

How long have you owned the car buddy , because the leak may have been there a while

We have had the car since last June, Dry as a bone until around new year then spotted the drops on the drive. It could be that it was only once the under tray was full that it would have found it's way onto the floor so you are right it could have been a long time. It just seems very suspicious that if this seal WAS the leak, the fact that they would have to have disconnected it during the service in October if it was already leaking I am sure they would have mentioned it.

The crux is I think there is too much oil for this seal but if it was it is down to them not refitting it properly, I just cannot prove it. I will be keeping a very close eye on it, regularly taking the undertray off.

 

[Martyn_n]

I'm no longer surprised to find badly fitted parts/car trim.
The top turbo seal takes a surprising about of force to seat it properly, at least that was my experience, maybe it wasn't seated.
But, being at the top of the engine I don't see leaking oil getting as far as the under tray, but depends on quantity.

Did you take off the under tray? Where was the oil?
Another oil source is the front of the engine. That large metal pipe running from the turbo to the front has several o ring seals.
Oil can leak from there. The pipe contains not just air but oil vapour from the turbo and probably the crank case vent.

Oil cooler leak. Yep, that's the big one. The 2007 W221 I briefly owned had this issue. Luckily I returned the car.
My current 2012 only has the lesser leaks mentioned. Fingers crossed.

The oil was coming from the rear of the engine, dripping off the bottom of the small pressed steel sump. I could not see oil above the line of the sump mating surface so my initial thoughts were the gasket / sealant around this part has failed but I have not heard of any cases of this being a problem, it always seems to be the oil cooler.

 

[Smiley]

Call me an old cynic but I would say that they are trying to avoid doing the oil cooler seals under warranty.....as soon as the warranty has ended they will then diagnose cooler seals.....Best bet is to get the car on a ramp and look for yourself. Take a video or photos.

 

[Martyn_n]

Call me an old cynic but I would say that they are trying to avoid doing the oil cooler seals under warranty.....as soon as the warranty has ended they will then diagnose cooler seals.....Best bet is to get the car on a ramp and look for yourself. Take a video or photos.

You may be right, but I would have thought they would love a day's work that they could off-charge to the warranty company. I will not be paying main dealer prices for the job.

My worry is that, even if I narrow it down myself, they will have it back in, get told the warranty doesn't cover "seals" and I'll end up paying the £168 investigation fee. I could get all the parts / fluids to do the job for that price and I have done worse jobs myself in the past, in fact I think I'd find it quite satisfying.

 

[Martyn_n]

I have just had the warranty booklet out. I think it is fair to say I have absolutely no chance of them sorting this out under warranty, pics attached.

 

[Martyn_n]

I have spoken to the service manager. I pointed out that it was a massive coincidence that the part they identified as faulty / leaking was removed and refitted by them a month before the car started dripping oil. He had no option to agree with me that had it been leaking / faulty at the time of the service it would have been obvious yet wasn't reported. He has agreed to pay for the next MOT as a "goodwill gesture" I have accepted and will move on.

Looking at mbmb123's other post today I think they all need to brief their staff on how to reinstall the "batwing" after changing the fuel filter!!

He still thinks they have fixed the leak (that they caused) but I am certain that, whilst I have little doubt this was weeping due to poor installation in October, this is not the root cause of my significant oil leak. I discussed the likelihood of the warranty covering the oil cooler seals and he said that the warranty is "very specific" about what is covered. The conclusion I have to draw is that it will not be covered.

Anyone have a complete list of gaskets I need to do the job?

 

[MrGreedy]

An old PCV valve will increase oil going into the turbo inlet seal.
I've just fitted a new PCV valve and pipework, here:

OM642 PCV Upgrade | Engine

Ah, so I need to replace it with A6420101891? Let's see how much mercedesofnewcastle sells it for

forums.mbclub.co.uk

However, as per BlackC55, who is doing this on a weekly basis, it is very very likely to be oil cooler seals.
I just cannot believe there will be enough oil, even from a failed PCV, to be pouring out under the car. The PCV oil is basically from crankcase vapour, not spoonfuls of oil (which is what the oil coolers will lose).
The oil coolers go from leaking, to gushing in a short period of time. Get it sorted ASAP.
MB Automotive in Loughborough charge about £870 for the oil cooler seals, including a new Mercedes oil cooler, but obviously engine specific and depends on what else they find when they do the job. You could save some money by not having the cooler replaced, but I didn't want to risk it as some coolers have been known to be cracked. And they you have to do it again. Aftermarket coolers are £50, vs I think about £125 for genuine Mercedes.

 

[Martyn_n]

An old PCV valve will increase oil going into the turbo inlet seal.
I've just fitted a new PCV valve and pipework, here:

OM642 PCV Upgrade | Engine

Ah, so I need to replace it with A6420101891? Let's see how much mercedesofnewcastle sells it for

forums.mbclub.co.uk

However, as per BlackC55, who is doing this on a weekly basis, it is very very likely to be oil cooler seals.
I just cannot believe there will be enough oil, even from a failed PCV, to be pouring out under the car. The PCV oil is basically from crankcase vapour, not spoonfuls of oil (which is what the oil coolers will lose).
The oil coolers go from leaking, to gushing in a short period of time. Get it sorted ASAP.
MB Automotive in Loughborough charge about £870 for the oil cooler seals, including a new Mercedes oil cooler, but obviously engine specific and depends on what else they find when they do the job. You could save some money by not having the cooler replaced, but I didn't want to risk it as some coolers have been known to be cracked. And they you have to do it again. Aftermarket coolers are £50, vs I think about £125 for genuine Mercedes.

I think you have summed up the conclusion I have arrived at. No way this much oil reaches the turbo inlet, let alone then escapes past the seal and then all the way to the floor. I will be looking at doing the job myself I think, quite like a challenge and saving a fair dollop of cash gives me an enormous feeling of smugness. It can't be any worse than the 612 inlet manifolds I've done in the past (and hopefully cleaner!). It's the wife's car so I just need to convince her I am up to the job!
Thanks for the heads up on actually replacing the cooler, I hadn't really thought of that.