That's what I'm thinking.
I've temporarily drilled a small hole in the fill tube cap to allow the air to escape, till I find out where the air is coming from.
I'm using the tractor sparingly for now.
I drained some oil and there's nothing other than oil in there.
When I unscrew the oil filler cap, there is a lot of air coming out of there.
So definitely air getting sucked in.
I have to figure out how the air gets in there and address the issue.
I have an issue with my '12 Mccormick tractor.
I have oil coming out of the dipstick even when the tractor has been parked for a long time. There is also foaming coming out at times when the tractor is in use.
Oil level was fine.