View Full Version : NCV3 OM651 - OIL LEAK at sump seal after six months use. Check yours!

08-31-2010, 08:07 PM
Every several weeks or so I like to get right underneath the van and have a look at stuff, just to check things over. Am so glad I did last week - couldn't fail to miss that my entire front sub frame / sump / tranny mount was covered in engine oil. I know it doesn't take much oil to make a big mess, but this really was a big old mess.

I started to look for the cause. The vehicle is six months and 30,000 miles old with OM651 engine. The oil was clean, and I wondered if somehow a load of it had been spilt when the vehicle was serviced a few weeks previously. It seemed like it would have been a lot of oil to spill though?

I couldn't find anything obvious, partly because of the amount of oil on everything. No oil level warning was given through the dash, although the actual level at the dipstick seemed a bit low considering how recently the previous service was done.

My first reaction was to think about cleaning the mess away and having a better look - I wanted the oil off and not getting into sensors / wiring etc. but really... it was the dealer's problem. Their diagnosis? Failed sealant gasket on sump. Apparently they don't have traditional gaskets there now, just sealant. Service manager told me they had done a few, in that frustratingly inadequate throw away fashion in which busy service managers do (have they?! have they not?!).

Cue a five hour wait for a two book hours job... Leak pronounced cured / mess cleaned up.

Before I left the dealer I scooched under some new NCV3s and had a look - there's barely any sealant visible at the sump to crankcase.

Sorry no pics folks but be sure to keep an eye on yours.

09-14-2010, 10:50 AM
Been thinking more about this event...

Although I'll never know the correct answers to these doubting thoughts I felt it might be worth making them public in any case.

I have an element of doubt in my mind that the leak originated from the sump to crankcase seal. These are the reasons:

1. I had looked underneath the van not long before it went in for an oil service (it's first). It was clean underneath.

2. After I had discovered the leak (very soon after oil service) I tried to identify the highest point at which oil was present on the engine. As far as I could tell this point was the underside of the power steering fluid reservoir.

3. The coincidence of the timing of the leak and the oil service.

4. Don't you think by now that DC know how to stick a sump cover to an engine?

It seems odd to me that oil which was claimed to be leaking from the sump seal at the crankcase could find its way so far upwards so as to be dripping from the reservoir for the power steering fluid. Maybe it's possible, taking air pressure at motorway speeds into consideration? I don't know, just seems odd. I would have thought it indicated that oil had run over the top of the reservoir for it to drip off the bottom.

Consider also the proximity of that reservoir to the engine oil filling point i.e right next to each other. There is part of me that wonders whether some oil was clumsily spilt down the side of the engine when the service was done, and then rather than admit and rectify a mistake an oppoprtunity was seen taken to make a few hours out of it as a warranty claim. When the service manager intially explained it to me, he was ever so slightly laissez-faire about it. Maybe he was busy that morning and didn't realise a fuller explanation would have been appreciated. A cynical person might have called it bullsh1t.

I think I'm right in saying that no one else has reported this on here before. This was also the first OM651 engine on here too - whether this is a factor remains to be seen.

I guess we'll see how many other similar claims are reported over the next few years and then we'll know more?

Still keep checking underneath though - I could be overthinking this.

Altered Sprinter
09-14-2010, 12:08 PM
Interesting comment Simon.
front seal crankshaft engine block v sump usually indicates a poor bearing seal or worse crankshaft wear.between bearing seal and crankshaft.
I'm not suggesting this is the cause to your engine.
However the oil leak/seepage will spin up wards. at high rpm.
I'm only saying this as to Fords Super pursuit engines under load, were notorious for failing at this point the culprit was the oil pump design long story. But the only solution to fix that seal permanently from weapage was to incorporate a speed seal.{i doubt if any one even knows about this remedy these days it's old hat}
I sincerely hope yours is just a one off.But thank you for informing us for the lads down under anyway.

09-14-2010, 02:00 PM
I realise I could totally have reached the wrong conclusion here - after all, who am I to question the dealer's diagnosis? It was just the limp delivery of their explanation that has made me wonder after the event. Also the fact that there isn't a single reported case of the same on any NCV3 that I know of in this forum (is an OM651 sump seal really that much different to another engine?). It's just a feeling, like when you later find out someone lied to you.

Altered Sprinter
09-14-2010, 02:33 PM
Well mate! You have a pending irritation to watch and observe. I guess time will tell .
But oddly enough one offs of parts failing for whatever reason do occur on any make,Thats why we have a warranty to iron out the bugs.

09-14-2010, 03:47 PM
Yeah that's fair comment - I could well be totally off base.

01-02-2011, 05:17 PM
Update: this leak is definitely BACK, or more accurately, not identified and fixed.

The previous repair to the sump to crankcase sealant appears fine. My thoughts are that it originates further back and higher up.

Will let you know what transpires this time.

01-07-2011, 09:56 PM
Any new findings?

01-13-2011, 06:54 AM
Yes Simon, it's back from the dealer.

They state that the leak was originating from the sump to crankcase seal AGAIN, and apologised for the need to have it looked at a second time.

With the first repair I drove the van from the dealer reasonably soon after the sealant had been applied to the mating faces. Whether the van was driven too soon or not I can't say, but this time it sat in their yard for twenty four hours before I collected it so it definitely had time to cure fully.

It is a little frustrating, but the dealer's support has been professional and pleasing.

I still don't know for sure myself where the leak sprung from, but will keep an eye on it and let you all know if it starts leaking again.

02-23-2011, 01:44 PM

There's more: I've now spoken with three other Euro5 owners who have all had the same issue.

I wonder if changeover Euro4 to Euro5 saw the disappearance of the sump to crankcase gasket too?

02-23-2011, 02:09 PM
Any chance of a photo...i can kinda visualize your issue in my head, to cold right now for me to look at mine.

02-28-2011, 07:47 PM
I do have a couple of snaps, will transfer them off my phone when I get a spare moment.

The latest update: the sump apparently comes in two parts, not just one. There is an upper sump casing and a lower one. Both these parts have been replaced under warranty this time, along with a third helping of sealant.

The issue appears to be the thickness of the sump wall: it is thinner on the wall nearest the transmission. Each time it has leaked it has come from the nearside rear corner of the sump casing (the one nearest the transmission).

Let you know how the new parts and repair hold up.

03-01-2011, 01:51 AM
I'm wondering why there should be a leak, unless the crankcase pressure (due to excess blowby or partially plugged crankcase vent to turbo inlet or partially plugged oil mist eliminator) is too high.

03-01-2011, 01:20 PM
Good points. I also contemplated crankcase pressure issues.

I can't explain it in any more detail at the moment, except to say the dealer suggests mine isn't the first he's seen. All those he has dealt with had the leak originating from the same point, which suggests to me a flaw in the sump design.

Aqua Puttana
03-04-2011, 02:37 AM
I don't remember the details, but I do remember a foundry tech friend of mine talking about leaks in some Dodge transmission products years ago. He said the aluminum castings were porous either due to thin design or quality control. He said something about "doping" being one of the fixes. He wasn't too impressed by that solution as I recall.

So I guess the moral is that all metals/castings aren't created equal and it doesn't necessarily need to be a gasket or seal that is the problem when it comes to leaks. Sorry my memory isn't better for the details. vic

Altered Sprinter
03-04-2011, 02:52 AM
Good points. I also contemplated crankcase pressure issues.

I can't explain it in any more detail at the moment, except to say the dealer suggests mine isn't the first he's seen. All those he has dealt with had the leak originating from the same point, which suggests to me a flaw in the sump design. Simon investigate and look for crankcase pressured leaks /oil separator of the engines breather system there are know problems with the fleece filter not correctly sealing and causing problems with the engine block and ECU re flash required,

03-04-2011, 07:13 AM
The old VW aircooled engines needed to have the crankcase halves sealed or they would ooze all the oil out all over. Got a batch from Brazil once that were all bad, turns out they skipped a step and didn't seal them. It was ugly. Hope that's not what's happening here.