I've had a problem with my 940 Turbo that seems to be a common one on this board. Although new to mechanics, I've read the 700/900 faq very closely and have been very proactive with my mechanic. I just got my front seals replaced due to an oil leak. Since January, my Volvo has leaked at the valve cover, the oil filler cap and recently the front seals. Everytime I top up the oil, there'll be a puddle of oil on the valve cover after a few kilometers.

Based on comments here, it would seem likely that this is a ventilation problem. I've replaced the y-adapter coming from the breather box and the little hose that goes to the intake manifold + ensured that the brass nipple is clear. Additionally, my menchanic has checked the breather box and I can breathe through the hose if I take the oil filler cap off. I have noticed, however, that there is oil residue on the t-joint where ventilation hose connects to the turbo hose.

My question/concern is as follows. How can I confirm that this is a ventilation problem and not excessive blowby. When I bought the car, I had a compression test done, which passed (all four cylinders were at 140 (or within 10%)). My mechanic swears up and down that the ventilation system is clear, but the car drives like it has a plugged nose (occasionally sluggish). The dealership wants me to get a leakdown test, but I'm wary of spending a tonne more cash.

Any advice or info would be greatly appreciated. This has plagued me quite a while.