Our XC90 with 198k miles just developed excessive smoke on start up and acceleration. When the plugs were pulled the #2 &#3 plugs were very wet with oil. Plugs and coils new less than 2k miles ago and an oil change at that time. The other issue that started at the same time is that, on occasion, the engine is slow turning and we think it may be related to the oil issue. Any insight would be helpful. Thinking the head needs to come off and check valve oil seals. Or could a clogged PCV valve cause an increase in oil pressure enough to push oil past rings or seals?

 

More than likely has to do with the oil control rings on the pistons. There were many 5 cylinder engines that got new rings under warranty somewhere in that year range for oil usage problems. You might want to check with your local dealer to see if this is a common problem and what year and engines have been/are subject to that free work. The valve guides and seals will not let much oil in - there is simply not that much oil near the top of the guide to get sucked in the cylinders (or sucked into the exhaust).

You can easily check the pcv system for excess pressure - remove the dipstick and put a pressure gauge on the tube. Usually it's the other way - the diaphragm breaks in the pcv box and allow too much vacuum in the crankcase, creating weird squealing noises and a noticeable vacuum on the dipstick tube.