? about blow by and oil contamination

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May 28, 2002
It's been discussed that cold weather and cold engine temperatures will cause more blow by than hot weather and hot engine temperatures. As an example, Patman's last UOA showed 1% fuel dilution in cold Canadian operating conditions. Whereas many UOAs show only trace amounts of fuel dilution. Obviously the PCV system pulls a lot of gasoline and other lighter hydrocarbons out of the crankcase and I know the actual amount of blow by will vary greatly due to many variables. What I'm wondering is what kind of quantities of gasoline is typical of getting by the rings in cold weather and cold start conditions? Also what type of fuel percentage in oil is still considered basically safe and at what percentages of fuel dilution start to get to the point where you want to get that oil out pronto? If anyone has any info on this TIA.
I believe most labs will flag it as a problem when 2% fuel gets into the oil. I personally set 1% as my limit.
2% is a normal limit, but usually there is something you can control to lower it and keep it at 0........ I've seen up to 23% in an analysis
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