Synthetic Oil Verses Standard Oil ?

[thumpar]

You should probably take off a head and look at it sometime. Valve seats are not an area that get oiled unless your engine has bad valve seals or bad rings.

That is what I am saying about the blue cloud coming out of a car. I know how they work.

 

[Lou C]

Bad valve seals or guides will cause oil burning....
About the oil, one factor that is important is whether or not the engine has an engine oil cooler. If it does the choice of oil Syn vs Dino is not so critical. If it does not then it is more critical. If Volvo says to use Syn oil Id try to stick with that, esp if that is what those engines were run on till now.
Having said that I have used both straight weight conventional and Mercs 25/40. I did oil analyses using both. The Merc oil stayed in viscosity as well even better than the straight 40. So I guess the manufacturers do know something lol.