One of my engines is producing a good amount of milky blow-by from the valve cover breathers. Oil in the pan looks perfect. Running Oil T-stats and have no problem keeping 190-225 oil temp. Not running any water T-stats and engine temp never breaks 100.

My Thoughts: With cold lake water (65 degrees) and no real engine temperature, condensation is building and mixing with oil in the valve covers then being blown out the breathers. However if this were true it would be happening on both engines. Perhaps i have some excessive crankcase pressure on this engine? Besides worn piston rings, is there any other logical reasons for one engine to produce more blow-by than the other. Or another logical reason for milky blow-by, with the oil in the pan looking perfect??

I'm no expert........but! Your oil temp. should be above 212 to boil off the water/condensation. With that said that looks pretty excessive. Like a head gasket perhaps.

You have a leak... That is way more than condensation. Condensation on the valve cover would be just a lite coating NOT the milkshake you have there. Do you have an intercooler if not pressure test the exhaust first. Next step is head gasket.

I do have chillers. Will pressure test it this week.

Intercooler if you have them

I'd do a compression test and also pressure test you manifolds,,if the chillers check out.you've got some blow by,hell,thats worse than when I had head bolts fail in the block while running.

I would take a close look at the intake, could be cracked or just leaking massively at the gasket. Also I am wondering how you are determining the oil looks perfect? If you are looking at it on the dipstick it will often look fine because water would sit on the bottom of the pan and oil would be on top, so you cant really tell by the dipstick. Need to look at the oil in the filter.

true but he would have raised oil level if water was entering...

it is easy to get condensation in Lake Erie I do early in season, this time of year and oil temps above 180 you really don't get it... I see no condensation now that's its warmer out and I don't have water stats...
can you look in oil fill cap hole and see condensation ??

Just went out for a ride and got oil up to 220 no problem, water temp never broke 100.
Shutdown and pulled dipstick, no water in the oil. if there was water id assume it to be mixed up after a run.
I don't see any milk or condensation when i pull the fill cap.

The more i think about it, even if an intercooler was leaking, I'm not sure how it would ingest water without sucking it through the engine, in which case it would be in the pan as well.

Is the milkshake under one valve cover or both? The reason I'm asking is I had a restriction in the water passages on one head a few years back and because of that most of the cooling water was taking the path of least resistance and over cooling the opposite head thus causing condensation on the one side. This would only apply if you're running a crossover.