Oil Cap rubber seal warping and leaking small amounts of Oil

[Swiggy]

I have a 2017 S4 with 63K miles and have started to notice that the seal around the oil cap has started to leak small amounts of oil.
I found that the rubber seal had widened on the outer part and was letting oil out past.
So I got a replacement cap and seal from the dealer for £28 and it cured it for a few days.

However I am now finding that the seal that sits around the outside of the oil cap is starting to warp again, this time from the inner end of the seal closest to the oil cap.

Has anyone seen this before or know what could be causing it?
Would it be the Oil Separator causing a bit of pressure for it to distort the seal and cause small amounts of oil to blow up and out of the main oil cap?

Much appreciated

 

[ub7rm]

I would say yes - you probably have excessive crankcase pressure and replacing the oil separator module should address the problem. I replaced mine because I was detecting a pronounced 'oil' smell around the intake side after a run and it was noticeable in the cabin after a restart. There is also a pipe assembly that goes from the separator back to the air intake which has one way valves in it - its simple (if gross) to test - disconnect and do the suck / blow test on it ... I replaced both so I wasn't doing the job twice but the pipe assembly was actually OK.

Make sure you order the gasket for the oil separator - it doesn't come with it.

 

[Spearo]

It’s the pipe with the one way valves in it !
something there gets clogged or blocked and pressure builds up in the air oil separator and pushes oil past the oil cap seal.
It’s an easy fix that doesn’t cost a fortune. Think mine was done at 75k and the pipe cost erm maybe 65quid ?