2.0 TDI 177PS smoking from oil filler

Newbie to Audi brand but generally know my way round cars and do most maintenance myself.

I'm looking to buy a 64 plate A4 Avant.

Just given one a test drive from nearly cold and pulled over after a couple of miles to listen under the bonnet and just opening the oil filler a crack it is blowing out oil smoke.

The dealer gave me what I think is load of BS about the EGR valve etc and claims they all do that. I'm not convinced. It has 55k miles on the clock and full service history

I also own a Ford 2.0TDCI (sorry to swear!) and that if anything has a slight suction with the oil filler cap right off which seems correct to me as the fumes should be being sucked out of the crankcase into the inlet manifold.

Anyone care to comment of the A4 normally smokes like this? Is it a common problem such as a blocked crankcase breather filter?

I like everything else about the car but not comfortable about this smoking.

TIA

Bump would be interested in this also.

The oil filler cap on my TDI when removed has some pressure behind it but as far as smoke goes I do not see any.

Hope some more members with TDI will come forward and share their experiences with what the oil filler is doing on their cars.

Thanks for your reply Sacha35.
I did not dare to remove the cap completely as it would have chucked oil out. Talking to my friendly repair man he suggested that some engines have a solenoid valve that only vents the crankcase above certain revs to keep the tick-over emissions lower. However a trip to the local main dealer parts dept, a Very helpful chap could not find a valve listed or shown on the diagrams for this engine. code CGLC

I reckon this motor had had a hard life and the rings were going. Although it drove quite well, it did not have the power that my 12 year old Cmax 136HP has and the Audi is supposed to be 175hp.
Still interested in others experience but I've walked away from this particular deal.

Bob