Thanks Hydrocruiser. Sounds perfect for my current situation. Statement "diluted by fuel" could be taken to mean that gas can be absorbed by the Motul oil but their additives, etc. are designed to resist viscosity reduction in the presence of fuel. I found no direct mention that fuel will not disolve in the oil. The link to their "technical information" appears to be dead.

By the way if Motul's base stock is ESTER what is the like term for the typical synthetic oil base stock like Amsoil or M1?

AMSOIL is 100% Poly Alpha Olephin and Mobil One is a highly refined petroleum product with PAO blended into it.

Mobil-1 and Amsoil are GRP IV Pao's. Atleast the $10.00/qt products are.

Motul and Redline are 100% Grp V. Double esters.


Esters have such a gigantic affinity to metal and extreme film strength that the gasoline has an extremely hard time finding it's way to the metal parts of the engine. It's like a chemical barrier to gasoline.


Now Motul is $15.00/qt but it's worth the $$ I feel if you idle excessively.

To monitor for gasoline let some oil drain off the dipstic onto a metal spoon. Light the sample...be careful and away from flammables....if you get an open flame it's gas.

Be careful!

I like the 15W-50 Motul. It is used for a full 24hrs in many LeMans race cars. It's a bigtime endurance product.

Run some and send a sample to check for wear numbers. (Iron/copper/lead)

Very interesting. Thanks.

Hydro

Is the Redline similiar to Motul? I see that it is a Group V, also. What is the price of Redline? Thanks.

Mobil 1 is a "full synthetic", a highly refined petroleum product with PAO base stocks. AMSOIL is a 100% synthetic, with 100% PAO base stocks.

Hydro, what are your credentials, are you a tribologist??? I was just wondering, since you seem so informed on oils.

Light a spoonful of oil? Really? To test for gas?

Is there an accepted oil industry test procedure to evaluate the wear resistance/viscosity characteristics of a motor oil when contaminated by gasolene?

I would say the best thing you can do is oil analysis. An analysis will tell you the viscosity of the oil, with or without fuel in it. But, really, you need to find the source of the gas getting into your oil, and just fix the issue.

Oh I totaly agree that fixing the fuel contamination is my first priority. I discovered very rich hot (not cold) engine AFR at idle rpm that I suspect is my problem. Once the ECU is recaled I will again test my oil to see it that was it.

I am just following my curiosity where it takes me on the fuel contamination versu oil performance question. Just trying to understand the source of the knowledge as to what type of oil base / modifiers / brand does what. More specifically is it theory or theory backed up by reproducable test results. I just want to be a knowledgeable buyer when I try to pick the best oil for my motor.