So I have milkshake in the valve covers on 1 of my engines. TNT says it's too much to be condensation, just pulled the intake manifold and they say it's not corroded and the leak is not coming from there. There is no milk in the crankcase oil. Where else could this leak be coming from? Engine is 1999 hp500

Sounds like condensation to me. ALuminum Valve covers???

If there isnt milk in the pan, it must be condensation IMO. If I have to idle for an extended period before shutdown, I see the same thing.

I try and get my oil-temp above 220 before heading for the trailer, seems to keep this issue under control.

I recently noticed that I would get some condensation inside the oil fill cap when I ran the boat on the hose for about 30 minutes, I will avoid that as much as possible in the future.

I am getting the same. I just redid my top end , I am still convinced its my intake gasket . I just installed another intake gasket and its still leaking. I am going to tryto swap out those little allen head bolts one by one and put a big flat washer underneith a hex bolt and retorque. Do you think that will seal it ?

Got an oil temp. gage? If the oil temp. is less than 212*F., then water (one of the products of combustion that will get into the pan and oil system) will not be vaporized and extracted completely through normal ventilation and will show up as "milk shake" on your breathers and valve cover fill caps. But, if you have "milk shake" elsewhere you need to check the gaskets or for that little crack that got missed at rebuild time. After confirming that your oil is reaching proper temp. then go to a leak-down test. --- Jer

If the oil in the pan is fine it is condensation, on raw cooled motors it is more of a problem then on closed cooling setups. Higher engine temp helps a lot. Some engines have PCV valves if you have them change them that will help some. Getting air to flow through will help, I put a breather on my port valve cover and two hoses off the starboard up to the air cleaner to draw more air but I also have closed cooling. Another thing is if you run in "fresh water" go to a 180 thermostat that will help to cure it plus you may find a tiny bit more power.

Phil

Yes, and I cant get a reading on it, never comes on, that engine has always run at 3 psi water pressure wide open (crossover no t-stat) the other runs 5 psi water pressure and has no condensation. I'm going to put the re-circ pump back on & t-stat back in. But in the mean time tnt says the milk has rusted my valve springs etc, and I need a rebuild? Any suggestions?

Post pics of the valve spring. How many hours on the motors? May only need valve springs. If your not over 250 hours on an Hp500 your should be fine. If you replace the valve springs use Isky Toolroom.

Your motor should have a oil thermostat, if not consider one.

my $.02

Dont you think if you stick 2 fingers in the oil fill hole and they come out green and foamy thats too much condensation or something more?

probably just condensation, however, if you let the motor sit for an extended time with that in there it will attack the valve springs and possibly valves.