Mobil 1 0w-40 Better Than GC Gold?

Messages
1,527
Location
Mid-West, USA
Okay, I am a GC Green user, but, I have never used the Gold. I love the Green, it works well for my VR6 Jetta. But, it is hard for me to get to Autozone, and there is an Advance Auto Parts about 1/2 mile from my house. They carry Mobil 1 0w40 SM for the same price as GC. I have seen many good UOA's of the Mobil1, but, a lot of people on here bash it. Why? I know that it loses it viscosity a little, but is still usually a bit heavier than GC. So, knowing that, and accepting that, what makes this oil bad? Why is it not as good or better that GC. I know the elves didn't brew it, so I guess what other reason is it not as good?
 
Messages
260
Location
Newtown, PA
I think a lot of people are dissappointed with Mobil 1 rather than the oil. The oil is pretty good, but it's not up to Mobil's usual standard of excellence. M1 T&SUV showed us the have the know how and ability to make a totally killer 40 weight, but 0w-40 is just kinda average.
 
Messages
5,785
Location
Dixie
The Mobil 1, 0w-40 and the GC, 0w-30 are basically identical in terms of high temperature, high shear (HT/HS) viscosity, which is the relevant parameter you should be looking at: Mobil 1, 3.6 centipoise @ 150C GC, 0w-30, 3.5 Cp @ 150C The problem with the 0w-40 is that it shears badly in precisely the kind of multivalve, turbocharged engines it's most likely to be used in. If the kinematic (low shear rate) viscosity @ 100C drops by 10%-15% (as shown by oil analysis), then the high temp, high shear viscosity drops by a comparable amount. The minimum HT/HS viscosity required by the VW 502.00 spec is 3.5 Cp. So after a few thousand miles the 0w-40 no longer meets VW requirements with regards to HT/HS viscosity. A simpler way of saying this is that you don't get 40wt protection very long with most 0w-40s. A better choice is to use an ACEA A3/B3 or VW 502.00 rated (but more shear stable) xw-30 or 5w-40. The best way to determine shear stability is to divide the kinematic viscosity @ 100C by the HT/HS viscosity @ 150C. The lower the quotient, the more shear stable the oil will be. FWIW, I highly recommend the Mobil 1, 5w-40 (ie Delvac 1) for this application if you can find it. TS
 
Messages
264
Location
Edmonton, AB
quote:
Originally posted by TooSlick: A better choice is to use an ACEA A3/B3 or VW 502.00 rated (but more shear stable) xw-30 or 5w-40. FWIW, I highly recommend the Mobil 1, 5w-40 (ie Delvac 1) for this application if you can find it. TS
What is the xw-30 or 5w-40 you mention? Also, is the Delvac 1 5w-40 the same oil but branded differently than Mobil 1 5w-40 truck and suv oil? Thanks.
 
Messages
5,785
Location
Dixie
e36'n, What I'm saying in general is that a 0w-30/5w-30/10w-30 that meets the ACEA A3/B3 or VW 502.00 specs is going to be more shear stable than a 0w-40. A 5w-40 will also be more shear stable and most of them will start out about 10%-15% thicker in terms of HT/HS viscosity. For example, Delvac 1 comes in at about 4.0 Cp, vs 3.6 for the 0w-40. Delvac 1 and the T & SUV oil are the same stuff.
 
Messages
260
Location
Newtown, PA
Yeah, M1 5w-40 is good stuff, I run it in my turbo saab. You could also go totally overkill and run castrol syntec 5w-50. I'm thinking of giving that a try at some point.
 
Top