Originally Posted By: Gary Allan
Again, ..no one seems to pay it any mind. That's probably the real thing that causes me to
I pay it a lot of mind. Those polymers add viscoelastic properties to the oil which can benefit bearings even when sheared. Those polymers also tick me off for other reasons like:
- Decreasing oxidative/thermal stability
- Increasing propensity toward deposits
- Possibly decreasing ring seal due to deposits on rings and piston grooves. This gives rise to all sorts of negatives like increased fuel dilution, more flow of nasties through the PCV system, increased oxidation and nitration, etc.
I think I could tell the formulators how to make a variation of this oil that would be better in some ways but it would get maybe no longer be a 0W oil and it may not pass the fuel economy requirements of MB 229.5. It probably would pass it for MB 229.3 though, as some 5W-40 oils do.
BTW, I've had bad experiences with Gold GC in both my vehicles. I think it gets its high viscosity index from a high viscosity index FLUID rather than a high load or polymeric VIIs. That gives the high shear stability but my testing did show that it is more volatile than M1 0W-40, which is interesting to ponder why. Clearly there is a relatively volatile fluid in GC but the details beyond that are what's interesting.
M1 0W-40 has more virgin TBN than GC, FWIW.