Weird smoking problem

[Silu]

Hi All,

Apologies for my English, not an easy thing to write about mechanical stuff being a not native

My car produces a lot of smoke, we're talking about a huge blueish cloud I see in a rear mirror - but it happens in specific circumstances only. I'm on vacation now and noticed the issue last week when I was driving on a highway, so I didn't have a chance to check anything or visit a shop. Here I'm just looking to narrow it down if possible.

So what's happening?

The oil/engine has to be warmed up to its operating temps.

1. I accelerate to mid/high rpms, the longer I push the gas pedal, the more it manifests later. No smoke at this point.
2. I lift off the throttle completely - no smoke.
3. As soon as I touch the gas pedal again - puff, a smoke cloud. I doesn't need to be WOT, it happens when I barely touch it as well.

It doesn't smoke on idle nor acceleration as already mentioned. There is more smoke when I stop the car or when I go easy for a while, like it builds up. When driving on a highway with constant higher rpms for a longer while, it is much harder to produce it.

I use quite a thin 5w30 oil - 9.6 viscosity in 100 C (212 F). I know, not an optimal choice, I'll switch to 5w40 shortly.

So what can it be?

- turbo? It seems to be turbo/boost related as I couldn't produce the smoke when I go up with rpms without boosting. I tested turbo for smoking on idle though - idling for 15 minutes, then revving to 3k rpm for a minute or two. and letting it idle again. No smoke.
- rings? Wouldn't they smoke on high rpms constantly?
- valve seals? I have a very slight white smoke on cold startup, it's gone when rpms go down after a while
- PCV valve? Not sure if these symptoms fit.

Any ideas are appreciated.

[MSMS3]

What is your static compression on each cylinder? Have you done a cylinder leak down rest and what is the result?

Have you read the scores of “smoking turbo” threads, assuming compression is ok?

What do your spark plugs look like? Any oil on any of them?

Test data will drive the diagnosis.