2001 502 mag mpi. Changed the oil after the winter everything look ok. put fresh oil in and started it up for a few minutes. Ran ok. Check oil and it has water in it. Drained and repeated and still milky. Raw water cooled no heat exchanger. Only about 10 hrs on new exhaust manifolds and risers. And just changed water pump impeller. Leaning towards oil cooler, intake manifold or cracked block. Boat has 370 hrs. Any advice would be appreciated😎

are you seeing this on the dipstick or in the valve covers? If in the valve covers its probably just condensation...if on the dipstick then you have an issue somewhere. Keep in mind it only take about a tablespoon of water to turn it into a milkshake....i've cleaned out a milkshake in the past by flooding the engine with a couple gallons of diesel fuel....turning it over by hand and run the oil pump with a cordless drill then drain and change oil twice to clean it all up...

Fresh water or salt? If salt, I would consider pressure testing the cooling system by blocking off hoses and adding compressed air via a schrader valve.

Its brackish. And I noticed it first on the dipstick pumped all the oil out and refilled it. Ran for a another minute or so and pump it back out and still milky

How was it winterized? ??

I poured antifreeze In the hoses at the thermostat housing into the block filled up and unto I heard it run out the exhaust

so you didnt run the engine just poured the antifreeze in there?

First I drained all the water and yea I just filled it. If I ran it would of just went out the exhaust

If you run it for awhile, does the level go UP on the dipstick?
I've milkshaked a few motors, nearly all head or intake gaskets.

That is really not the way to winterize. Water can get trapped in block even if you drain. I have pulled motors and drained what i thought was everything in block and as i move the motor around more water comes out. I have an xr drive and after i drain the block header and oil cooler. I add the pink stuff in hose that goes to impeller and wait till it comes out exhaust. It usually takes me 8 to 10 gallons and i start to get pink out of exhaust around 6 gallons. I do not run a thermostat but a reducer washer and have noticed when flushing on the hose i will get condensation in the valve cover. But after coming back from a run its all gone.