Here is the story.
My car has been sitting since last winter for a rear transplant.
I would start it at worst every 2 weekends just to get the oil flowing for like 5 minutes. Curious one afternoon, I uncapped the oil cap and found it to be sorta milky under the valve cover. Also saw that on the base of the cam lobe that you can see as you look inside the oil cap hole, there was/is some rust build up. So I ran a compression which turned out ok for kicks. But most importantly, ran a leakdown test with the radiator cap off, to see if pressurizing the cylinders would make the antifreeze in radiator flow out. But the antifreeze was sitting still and there was no bubbles either.

Normally I would know right away with a leakdown test if the headgasket is blown.
Both times I have performed the leakdown test cold.

My question is: Could the milkyness under the valve cover be just water condensation build-up under the valve cover since the car's been sitting for long, although I've been starting it every 2 weeks since last winter.

 

You are starting it every two weeks and not warming it up enough. This is how you build sludge. It would be better not to start it for a few months and not make sludge. Just charge the battery.

 

This is true. A few of those times car got the luxury of a full warmup

so you are saying this milky substance is probably sludge?

 

^its water condensation. it happened to my car when it sat for a while

 

ok thats cool, thanks

I just never ever noticed it before. The only times i've seen it was when my headbgasket was actually blown.