My Volvo s80 2004 2.9 which is a non turbo and done 135k has a bit of greyish smoke coming when I take the dipstick out. I'm not sure whats causing that.
I recently changed the oil and constantly do every 10k. Oil filter is changed, engine is smooth, although there is a bit of oil leak from the timing seals, could that be it ?

Other than that there is a bubbling (boop boop) sound coming from the engine, Volvo said it might be the water body but they're not sure yet.

Any suggestions or advice ?

 

Sounds like your PCV system is clogged up. These things call it an oil trap but when it is congested it increases crankcase pressure - blowing the cam seals.
You can google it and likely find a tutorial for it - it is a pain to get to but doable.