Mobil 1 FS 10W-30 Jeep 4.0L 3000mi OCI

[MechEng13]

I would doubt that result as being accurate.

Seems like this is a pretty standard way to test for fuel dilution. Both Blackstone & ALS use flashpoint. I blame the oil, but others can make their own assessment based on the above information.

What is a Flash Point? | Blackstone Laboratories

www.blackstone-labs.com

 

[kschachn]

ALS Labs states that they use calculated viscosity/flash point to determine fuel dilution. Given that this engine is fuel injected and just about everything in the fuel system is new, I have my doubts that the shear is due to fuel dilution. Does anyone know the average shear after a standard OCI? 0.8 centistokes does not seem significant, but I am open to learn from the BITOG experts.

And unlike fuel dilution, mechanical shear is completely dependent on the oil being used. And more specifically on the amount and quality of the VM used by the blend(er). One could easily test this by using a monograde oil if your climate allows this. Monograde oils do not shear.

 

[kschachn]

Seems like this is a pretty standard way to test for fuel dilution. Both Blackstone & ALS use flashpoint. I blame the oil, but others can make their own assessment based on the above information.

What is a Flash Point? | Blackstone Laboratories

www.blackstone-labs.com

Yes it is a standard ASTM test. However it is an inferior method and can be wildly inaccurate. We have seen Blackstone results here that when retested via a direct measurement method (gas chromatography) are nowhere near the same.

This method would be better classified as preliminary screening rather than a definitive test. You're relying on an a test (flash point) that already has poor repeatability and reproducibility, then you are inferring a secondary value from that.

ALS may test by a direct method if you pay for it. I would ask them, and if possible have the sample retested.

 

[kschachn]

Seems like this is a pretty standard way to test for fuel dilution. Both Blackstone & ALS use flashpoint. I blame the oil, but others can make their own assessment based on the above information.

What is a Flash Point? | Blackstone Laboratories

www.blackstone-labs.com

You can do that if you wish, but Amsoil 10W-30 uses relatively little VM and they also use one of a high quality. Mechanical shear would be one of the last things I would expect from that oil.

 

[MechEng13]

You can do that if you wish, but Amsoil 10W-30 uses relatively little VM and they also use one of a high quality. Mechanical shear would be one of the last things I would expect from that oil.

I will check with ALS and see if they are able to do a GC test next year.
This Jeep is usually driven for 30-60 minutes at a time. Fuel dilution from short trips and idle time could be a factor.
I will be testing another 4.0L Jeep with similar driving habits next January. I will compare the two viscosity numbers in this thread.

 

[Triple_Se7en]

I am fine with the Amsoil 10w30 UOA. It finishes at 9.3 cst@100 and likely started at 10.3 cst@100. If you factor-in fuel dilution, this oil showed very-very little shearing, if any-at-all.

I wouldn't put a reason for changing to Valvoline as cost-per-quart of Amsoil. Doing two OCIs per year means the Amsoil costs you around $25 more per oil change ($50 more per year).
My vehicles are worth that - versus me changing back to Valvoline, which I stopped using when the product was sold to a corporation inside Saudi Arabia.

 

[wlk]

I would run Maxlife blend red bottle 10w40 or QS All mileage 10w40 in the 4.0l. I had a 97 with it and startups were always quietest with the 10w40 over 10w30. I sold it to a coworker with 180k and I still see it around town 11 years later. Great vehicles