Just before winter I started noticing smoke clouds when accelerating hard on the highway, I could see it in the car headlights behind me.
I went for vacation down to Florida in Dec and used 1L of oil in 1400km/870miles. My car had never really used oil before. On start up when leaving the car overnight in the garage white smoke billows out the exhaust pipes. The white smoke only lasts for a short time (10sec) then it stops.
I did change the high flow PCV at the start of November with a brand new PCV from the dealer, as the previous one was leaking a small amount of oil around the rocker cover. I can see there's a light coating of oil in the breather pipe after the PCV. I don't have the old PCV to throw back on to test.
Is there any way to determine if it's the PCV, valve stem seals or possibly something else?
My mechanic was saying it could be valve stem seals due to the start up smoke, but he's not too keen to look into it, as he doesn't want to tackle replacing vs seals.
(2006 XJR with 145k miles/233k kms)

Thanks.

 

Oil would be blue-ish smoke, more than white. If it's a misty white, that would be water, as in coolant. A had a car once with a crack in the head would drip coolant into a cylinder and puff steam on startup. Steam is not smoke, though, and I'd think you'd see the difference.

 

I'm not losing any coolant, it's not water vapor/steam. It's similar to the smoke in the photo.

 

Saw this on the XJR. Very intermittent.
Was getting a CEL also every few months. Slow O2 sensor. The other front O2 sensor was running rich. Replaced all four, no white smoke, CEL’s, and fuel trims are back to spec.
Try pouring solvent through both CVV. You may be pumping oil.

 

my old BMW billowed white smoke when the crankcase vent valve gave up. good cats get rid of a lot of the blue tint

 

you might try cleaning up the PCV valve. Remove and pour a solvent through tosee how much crud is in it. They come apart for a good cleaning. It looks like a flapper and spring inside.
I had one on an Audi start to honk. Bought a cheap one. Started to honk and put the old one back on. Just cleaned it up inside. Ran it for 20,000 before replacing with a Vaico recently.

 

I used some MAF cleaner spray to clean out the PCV valve and went for a drive. Started her up this morning and smoke was still coming out of the exhaust.

I have an oil catch can, I just need to find connectors and rig it up, this should prevent any oil getting through the PCV valve if the PCV valve is the problem.