Milky oil in rocker covers - breather filter?

[loco]

Hi all,
So I've been getting milky oil in the rocker covers. The oil in the sump is fine, and the engine is only 2-3 years old, so I'm pretty sure it's nothing serious.
The engine uses raw water cooling, and sea temp here is between 8-15C (46-59F) so runs a bit cooler than closed cooling, so won't burn off as much moisture.

There are breather hoses in each rocker cover, with something like a 1/2" pipe coming from each of them, and they're fairly crudely attached to the air filter. I'm pretty certain that when the engine's been cooling down, it's been drawing in a load of damp, humid air with it, which is causing the nasty oil in there.

What are the potential solutions here? I'm thinking some kind of filters on the breather pipes to prevent humidity getting in, or something similar.

Any ideas very welcome!!

Thanks in advance.

 

[Scott Danforth]

What is engine temp showing? should be a 160 degree thermostat

at low temps, some condensation is normal. my guess is that you have been doing a large number of small trips and not getting any heat into the oil. If it was my boat, I would grab a bunch of beverages and sandwiches and put an hour or two at 3500 RPM or above and go for a long cruise to get some heat into the oil to get the moisture to evaporate.

or simply change oil

 

[Bondo]

What are the potential solutions here?

Ayuh,.... Solution,..?? It's normal, No problem,....

There's always humidity in the air, the valve cover cool the soonest,....

Take it out, 'n Run it for a few hours, 'n Look,...
There'll be no milky crud in there,.....

 

[loco]

MAny thanks!
yes, you're right - lots of short fishing trips just 10/15 mins out from the harbour. She's due an oil change, so I'll take the covers off, clean it all up, and swap it out. I was thinking of something like a valve/tap on the hoses that you close when you're not using the boat, or even an electronic one that opens up the breathers when the ignition is on, etc. Suppose that could cause a low pressure/vacuum when the engine cools...

 

[Scott Danforth]

MAny thanks!
yes, you're right - lots of short fishing trips just 10/15 mins out from the harbour. She's due an oil change, so I'll take the covers off, clean it all up, and swap it out. I was thinking of something like a valve/tap on the hoses that you close when you're not using the boat, or even an electronic one that opens up the breathers when the ignition is on, etc. Suppose that could cause a low pressure/vacuum when the engine cools...

Your over thinking it. Burn some fuel, enjoy The ride, get the engine up to temp.

Again, what is the temp gauge reading? Should be between 160 and 170

 

[loco]

ha ha, ok!
Would running a hotter temp gauge help at all? Maybe 180F? Never understood why raw water engines had to run colder and therefore less efficiently.

 

[jimmbo]

All the salts and minerals in the water come out of suspension at high temps and stick to the walls of the water jackets. It happens in you auto too, except you aren't always replacing the water on a continuous basis. Once the particulates are out of suspension that's it. But with raw water cooling, it's always new mineral/salt laced water

 

[PatinIdaho]

A Salt/Brackish water boat should have a 140deg thermostat or mineralization can occur. Fresh water only boat a 160/170deg thermostat can be used safely