Oil leak after service

[Rabt]

I recently had my ML 350 diesel serviced. The car has done approx 20 miles since the service and an oil leak has appeared under the car. The oil seems to be dripping from where it joins the gearbox to the engine. There looks to be drains where oil is dripping from.
I was told it may be a oil filter seal that has been nicked when fitting the filter, is this possible and to have the oil dripping from where it is.
The service was engine only.
Thanks in advance for any info.

 

[OlafMaxwell]

Its not uncommon and a good thing is to check over oil filters after fitting to ensure no leaks. I do all my servicing and it has happened to me occasionally, most recently in the last 6 months.

 

[malcolm E53 AMG]

Could be oil cooler seals unless the garage has messed up fitting the filter, if it’s dripping check your engine oil level the oil finds it’s way down from the oil cooler in the vee to where the gearbox mates to the block so certainly needs checking out

 

[sheryllee]

It is a common issue and must be checked for leakages after servicing.

 

[D5meister]

Could have removed filter oring and forgot to put the new one on.

Or could have fitted new one and left it dry on re assy it may have snagged, lipped out and been pinched/sheared

 

[Cole@MBS]

Oil filter is at the front of the engine, as said, oil cooler seals is my guess!

 

[Funkyboy]

Take it back and get them to check

 

[Uncle Benz]

If they removed the sump plug it’s possible the leak is there, either because they didn’t replace the washer, it wasn’t tightened correctly or the washer was damaged. Sure, it could be other things. Take it back is my advice.

 

[star]

Thinner oil finding its way out?

 

[Rabt]

Thanks to all who got back.
It took a while but I managed to get the car on a ramp, the oil was running down and dropping where the engine bolts onto the gearbox, it did smell like engine oil as opposed to gearbox. I managed to speak to a Mercedes mechanic who said its most likely the oil cooler seals that have failed. It apparently a fault with this type of engine. There is a Viton replacement seal that is now fitted which should eliminate this problem. What I have been advised to do is replace the oil cooler as well. As a pump engineer I can understand the Viton replacement. But unsure why the cooler has to be changed, unless its blocked, but surely this wouldnt allow the oil to flow. If they block up cant they be cleared.
Thanks again, car is still off road.

 

[star]

We replace the oil cooler as matter of corse, due to being caught out by one leaking and given the amount of work involved.

 

[Uncle Benz]

Two reasons we change the cooler.

1. it’s a big job to have to do twice

2. its a flat face design. I’ve seen them become corroded on the cooler bottom face close to the seals. Corrosion build up can occur between the two flat faces and lift the cooler up, effectively weakening the seals.

The cooler is relatively cheap in the great scheme of things. About £100.

 

[Rabt]

Thanks for getting back so quickly. We have been quoted £144 for the cooler and £33 for the seals both from Mercedes.
Given the advice it looks to be a false economy not to change the cooler as we were told by the Merc mechanic. I was just interested as to why it was changed and if anyone had changed the seals without the cooler and encountered any later issues.
Thanks again to all who got back, its much appreciated.

 

[alexanderfoti]

I agree with both Uncle benz and star. Its a false economy not to change the cooler, and often impossible to clean the corrosion to get a good sealing surface. Don't forget all the seals (inlet manifold, Cooler pipe o-ring, intake o-ring etc.)

 

[Botus]

if its a tractor - would it not then make sense when this far stripped - to always do the injector seals


...and check / change the glow plugs (if its around the right mileage ?)
...and the stupid swirl flap disaster (if its around the right mileage ?)

 

[alexanderfoti]

if its a tractor - would it not then make sense when this far stripped - to always do the injector seals


...and check / change the glow plugs (if its around the right mileage ?)
...and the stupid swirl flap disaster (if its around the right mileage ?)

Swifl flap, yes, as it needs to come out with the inlet manifold
Injectors/gp no as they do not get touched during this procedure, other than to remove the fuel lines/rails.

 

[Uncle Benz]

Another tip, if you want one. The bolts that secure the triangle flange at each exhaust manifold are copper coated single use items. Please fit new ones. If used a second time they will most likely be impossible to remove without snapping. I’ve had to deal with this myself. It put many hours on the job