Fuel dilution on purpose?

[Greg Bohn]

I have a 2002 Toyota with a V-6 1MZ-FE engine (referred to by some as a 'sludge Monster', at least in it's prior year incarnation...).

I've always had UOA reports show a 'thin' viscosity since it was new (usually in the 7.6-8.0 cSt range for 5w30 'dino' oil with only about 2K miles/ 4 months on it).

I asked the dealer about this, and he said Toyota does this on purpose. He said that in an attempt to reduce the chance of 'sludging', Toyota made a change to the engine to purposely have the oil thinned by some fuel dilution.

Anyone else heard of this? Would you try a 'thicker' 5w30 to try and keep the viscosity higher?

The used oil analysis sometimes come back with some fuel dilution flagged, but seem to always have 'good' wear metal levels despite the low viscosity.

Thanks;

-Greg

 

[pitzel]

Interesting question. Would adding a cupful of petrol to a crankcase fill of GC make it into a 0W-20 oil, for use in those Honda engines requiring 5W-20?

How long does fuel dilution actually persist in oil? Evidence here seems to suggest that fuel dilution pretty much dissappears once you have driven a vehicle for a few hours continuously, the fuel sucked up by the PCV system.

Would it be better to use diesel fuel as the diluant instead of petrol? A shot of biodiesel for extra ester content?

 

[2005tundra2002yz250f]

quote:

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Originally posted by pitzel:
Interesting question. Would adding a cupful of petrol to a crankcase fill of GC make it into a 0W-20 oil, for use in those Honda engines requiring 5W-20?

How long does fuel dilution actually persist in oil? Evidence here seems to suggest that fuel dilution pretty much dissappears once you have driven a vehicle for a few hours continuously, the fuel sucked up by the PCV system.

Would it be better to use diesel fuel as the diluant instead of petrol? A shot of biodiesel for extra ester content?

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I would think you dont want fuel in your oil. There are betters ways to thin oil. From what I gather, its hard to get the fuel out. Moisture yes, fuel no. Im sure someone will correct me if Im wrong.
joe

 

[wileyE]

Bad idea IMO. A cup of gas = 1 stick of dynamite
Not a good idea to make the crank case gasses any more volatile than they already are.

I also doubt toyota designs blowby into their ring packs.

 

[Big Jim]

This sounds like a flakey answer. Unbelievable.

 

[Whimsey]

Intentional fuel dilution, I doubt it. Sounds like your dealer doesn't want to do warranty work. Bet you when the warranty is up he'll only be too happy to "fix" the fuel dilution problem for you on your "nickel" . I suppose if you don't get it fixed you can always run Amsoil. That oil seems to thicken up in viscosity after a short time period. Your fuel dilution problem might keep it in grade

. Best to get it fixed though.

Whimsey