Originally Posted by BlueFocusSE5
You made the statement that Mobil 1 5W-30, "is garbage". Does Exxon/Mobil know this?
Of what particular experience does a company that manufactures heavy duty diesel oils have to offer gasoline powered cars?
Used oil analysis is to determine the condition of a particular engine and it's oil and not to make broad generalizations.
The 5w30 mobil1 has been known to act as a 5w20 due to it's premature shearing. This is specific to the 5w30.
And rotella is not just for diesel, it's for gasoline vehicles as well. It has better/more detergents to last longer and provide better results.
here are a few quick examples that I pulled up just now, there's a ton of data on this so get off your high horse:
There are plenty of UOAs on bobistheoilguy.com that show Mobil 1 5w30 performs poorly.
look at viscosity results
Here's a 2011 wrx w/ 5k on the odometer
here's a 2011 STI w/ 3k on the odometer, Rotella on the left, Mobil1 5w30 on the right
M1 EP 5W30 7538 Miles - 2011 WRX - Bob Is The Oil Guy
Mobil1 5W-30, Subaru WRX, 4,900 miles, Cu prob? - Bob Is The Oil Guy
1k miles on odometer
Mobil 1 EP 5W-30, 7232 mi, 2000 Subaru Impreza 2.5 - Bob Is The Oil Guy
all of these show mobil 1 breaking down to a 5w20 within 5k (as early as 1k in some UOAs)
I highly suggest you browse bobistheoilguy. Turbo cars are much more abusive on fluids. And in hotter areas, the 5w40 holds up extremely well.