2004 V70 will sometimes leave a hand-sized oil spot, under front of engine, after short drive. Other times, no leak at all.

It did have a leak at the oil fill cap, but a new gasket fixed that. The cap does not leak now.

Crankcase ventilation was serviced 5000 miles ago, all new parts. Plastic film over oil fill shows vacuum. No fumes from dipstick tube.

Any ideas which might explain this conundrum?

 

Look at the turbo oil return, that's a common issue. I re-did the oil pan to block seal with anaerobic sealant which solved about 70% of my leak problem but the real drip source was straighter oil cooler line lower hose crimp. I had a hydraulic/hose shop specialist re-do both of my oil cooler lines (4 new crimps and hoses onto the stock steel tubing) for a whopping $9. Yes, nine dollars. Unbelievable. I don't know how much new ones at the dealer are but I bet they're expensive.

It was hard to pinpoint the issue because when that cooler line wept it got oil all over everywhere on the engine/trans/pan/axle shafts you name it. Wipe it all down and see if you find where it's coming from after a short drive.

It's chore to do the pan and oil cooler lines, but with the proper tools, time and patience (and youtube guidance) it's about a 4 hour task.