Oil foam?

Why does oil foam up? I have a Chevrolet v6 that runs off natural gas powering a pumpjack, noticed this morning the sight glass for oil is full of foam??

Water in your oil. Could be a number of ways it got there; cracked block/heads, bad head gasket(s), or simply condensation.

dont rule out condensation...if the engine is not run very often, condensation can be an issue.

I had that issue with my 4.3 V6 when I was only making very short drives with it irregularly...

what kind of oil are you useing?

Don't know where you are but this year has had excessively high humidy and leads to a lot of moisture accumulations in many places including our engines if not run long.

Conoco has 17 varities of oil for natural gas engines. http://www.conocophillipslubricants.com/brands-products/Results.aspx?product=Natural+Gas