Head Gasket?

[Cubsox]

My 1937 F12 starts but runs rough. Keeps fouling #2 cylinder. Smoke is clean - not white, black or blue - just clean. Oil level increases with oil becoming thin and murky. Changed oil and cleaned plug - run for a while a couple times and same thing happens. I suspect water is getting into oil though coolant level does not seem to change noticably. Head gasket? cracked head or block? Problem with the fouling of the #2 cylinder makes me think head gasket. Any theories are greatly appreciated.

[Jim Becker]

How about a leaky fuel pump letting gas into the oil? Once the oil is diluted and overfull, it will suck more through and try to burn it.

Gas in the oil will tend to wash more crud from the inside of the engine into the oil making it dirty. Water mixing into the oil will tend to make it milky. So its your oil more murky, mucky or milky?

[Cubsox]

I was wondering if it is possible for the fuel pump to leak. The oil seems more mucky and just plain thin with a smell of fuel rather than oil. I will see if i can rebuild the fuel pump. I let the oil sit for a week and it does not seperate so would that also indicate is is more likely fuel contamination or does oil / water just not seperate with detergent oil additives? srj

[Jim Becker]

smell of fuel

There's your answer.

If there is enough water mixed into the oil to noticeably raise the level, there is enough to separate. But it may have to stand a long time before it shows.

[Cubsox]

Changing the fuel pump is easier than changing a head gasket. I think i will start there and hope for the best. thanks, srj