HDI high pressure fuel pump gasket oil leak?

[yason]

Anyone had engine oil slowly seep from between the high pressure fuel pump and cylinder head on an RHH engine?

I had, I replaced the gasket -- twice, the new one if from Elring, but it still leaks. Also tried adding a thin layer of sealers around the gasket but it just seems to be pushing through.

The leak isn't big: I never had to add oil due to this leak during the whole year. It also doesn't mark the parking spot. So no real problem there. It's just irritating to see the otherwise dry engine covered in oil mist (although the problem could also be considered involuntary rust protection for the back side of the engine...)

The leak is engine oil, not diesel. (The fuel side works fine, great pressure regulation and engine starts splendid right away so injection is 100%.) It's hard to pinpoint since the oil spreads thin around. I first thought it's the pressure regulator bolted onto the HPF pump but it's just the casualty of the oil leak. The leak must originate from the bore hole through which the camshaft drives the HPF pump. See the attached image: the exploded view lacks the said gasket (which sits between the pump and the head) but it should get your bearings right about the location.

Surprisingly there aren't that many posts about this in the PSA world but looks like Fords with the same engine seem to suffer from a similar leak. See here, for example:

https://www.talkford.com/threads/mk4-le ... et.409477/
https://www.talkford.com/threads/mk4-5- ... ak.279346/

It seems there's no definitive solution, however. Replacing the gasket worked for some but many reported the new gasket leaked right through within days.

I wonder if a thicker layer of gasket material, either additional paper gasket or just more silicone (or both the old and the new gasket together with silicone in between?), could help there if the side of the cylinder head isn't 100% true for some reason? There seems to be a seam going through the borehole, based on the image. The pump is connected to the camshaft with that coupler so it doesn't matter if the pump sits 0.5 mm further or closer anyway.

But my question is, has anyone seen this problem on PSA cars?

[kantica]

Don't apply silicone, this will not help. Also gasket is fine you need to change oil shaft seal on input shaft of the pump. Example seal would be Corteco 20034237B.

[yason]

Oh, you mean the one that you can see from the inside (engine oil side) when the pump is on the table, right?

Where does the oil leak through on the other side (HPF pump side) of the axle seal then? Is there a weep hole between the engine oil side and the diesel side? That kind of location would be spot on, the oil definitely oozes out somewhere from below the bore hole. I didn't see as much leakage around the actual gasket itself as what I would've expected when I took it apart: this would all be in line with what you described.

Much thanks! I'll order the seal and take the pump on the table one more time...

[steveclv]

Did this solve your problem? I seem to have exactly the same symptoms and will be changing out the seal based on kantica's suggestion.
Thanks

[yason]

Yeah, I didn't want to answer too soon to make sure I got it. Been driving it a couple of months now, and it was dead dry under the usual places now that I checked. So thanks much everyone!