TDI Oil leak. Sump or rear crankshaft ?

O

oko

A2OC Donor
My TDI has developed an oil leak at the junction between crankcase, sump and gearbox; towards the rear of the car.
Initially I thought it was coming from above, so wasted time replacing the rocker cover and tandem seals, however now Im sure it is either the sump or rear crankshaft seal. The DMF was replaced three months ago and it may have started then, gradually getting worse. The crankshaft seal was not replaced, but is only 6 years old, since the last DMF. As the leak takes over a week of non use, before it stops is that a clue that it is more likely the sump? My guess because of the angle of the engine it takes time for all the oil in the top of the engine to run down the side to the join with the sump. How long is the crank seal likely to leak after use ? I could probably replace the sump but no way attempting a gearbox out job. Sorry lost photo and all is now wet. Opinions invited with thanks.
 
Did you replace the rocker cover gasket correctly and use the beads of silicone? Check the oil filler cap "O" ring, the breather hose and its connection and the EGR or ASV valve. Turbo oil pipe can also leak.
 
Thank you
All dry now up top. The ASV was a long time slow leak which made me think it was the rocker. This is a fairly significant leak starting low and can be seen on this photo.
Either sump was not done well enough or how easy/difficult is it to damage the crankshaft seal on refitting the MYP gearbox ?
 

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Is it definitely engine oil and not diesel? Turbo oil pipe or even oil level / temp sensor could be the cause of the leak. How much is the oil level dropping? Pretty hard to damage the crank seal fitting the gearbox.

Give the engine a very good degrease to remove the current oil then fresh oil will show quickly.
 
If you zoom in to the photo above you can see fresh oil coming out of that corner between box, sump and engine block.
Its good to know it is hard to damage the seal, as I know they struggled with the MYP box; either taking off or refitting.
The sump was taken off as the timing belt and chain were replaced as well, at 290k they were all original and showed surprisingly little wear/stretch. I've hardly used the car in the last month but it is making a mess of the drive as it drips for long after use.
 
Sorry for the delayed solution. It was the sump seal. Sump was replaced for the timing chain replacement after the DMF, hence mechanic found it difficult to get to the sump screws. I struggled too to get the sump back without scraping the new seal goo. So if sump needs to come off with an MYP it may well be worth separating the gearbox to some extent (1-2cm?)
Thank you @audifan for your suggestions.
 
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