I have driven and worked on SAABs all my life, but my girlfriend just bought a really nice '98 V70 T5 to replace her ailing 900. It's very low mileage, not a spot of rust on it, and has beautiful paint and interior (except for driver's seat, which has three popped seams).

Anyway, this car had very low mileage (60,000) and had been sitting for a few months when I got to it. On the advice of a friend, I warmed it up slowly and carefully and changed the oil and filter (used a good, reputable filter) to avoid any problems with stuck valves. It's been used daily since then, clocking about 60 miles per day (long commute). The engine runs great, pulls strong, sounds fine, no misfires or anything.

The weird thing is, it starts completely silent, but after fully warming up the lifters tick. And it's the cylinder on the passenger (right) side of the car that makes the most noise. This is the cylinder closest to the oil feed for the head, so I would consider it least likely to make noise. I've read about oil pan O-rings causing problems like this. I think the oil pump is sucking in air through bad O-rings, and the lifters closest to the feed tube are catching it. I did check for bubbles on the dipstick, and there are a few, but only when warm.

Do you experts concur with my analysis? Is it time to drop the sump and replace the O-rings? I could always connect an oil pressure gauge to check further, but that is a pain (making up an adapter for my gauge, etc).