Originally Posted by Navi
The engine starts fine with any oil.
I think JButch knows my issue with 5W30. He has a turbo direct inject Subaru. Basically my engine and JButchs engine tears the 5W30 viscosity down to a 5W20. As for the Mobil 1 0W40 it also tears that down too which is why I shy away.
There is a short list of oils which it cant tear down too far like these HDEOs. As for the 5W40 you usually end up as a 5W30 viscosity.
Of course Ford says all this is perfectly ok but do you trust their advice or throw in the next grade up.
A new engine costs 10 grand btw...
Never quite made the jump to 40 weight, but I prefer C3/E6 5w-30 oils for my Turbo GDI.
I agree with Navi that GF5 5w-30 oils will shear to a 20 grade oil in our engines, in all the UOAs I did with those oil, they were in the 20 grade, some close to a 16 grade...
I had excellent results with either Rotella T6 Multi-Vehicle 5w-30 or Mobil ESP 5w-30, they both stayed in grade.
Rotella MV is SN+ and Mobil ESP isn't, but has low levels of calcium, I wouldn't worry using that oil in a LSPI prone engine.
They are both Low SAPS.