merc 165 milky oil out of crankcase vent

[johnzonh]

hi guys, before you harass me about my engine (yes, the alt rotor is still putting out just fine and the fuel pump hasn't flooded me out yet ) after finally getting it started of course got the bad oil....it has had a history of replaced head gaskets...is this a likely scenario every few years? The closed cooling is working pretty well... as far as I can tell no block issues...and I don't mind replacing gaskets. Was there ever a PCV on this engine? the guy I got it from didn't have one..and oil sludge came pumping out of the valve cover hose... would the lack of a PCV cause this to happen (regardless of the oil color)


any thoughts on this?? I will open it up next week.

 

[Maclin]

First thoughts are regarding the frequent gasket replacements, sounds like one or the other or both of the head and block may need to be decked at a machine shop.

As far as PCV, not real sure about yours but most late 1970's and beyond automotive-style sterndrive boat engines used a PCV housing with no innards in the valve cover, and a hose running to the flame arrestor or real close to it anyway. My V8 has empty PCV housings and hoses that go to fittings on the outside of the arrestor and the other end of the fitting is about 1/8 inch from the arrestor screen and the engine draws in the fumes.

Pumping oil up and out the PCV hose usually means the oil is too full (or "making oil" from water intrusion into the crankcase), or the engine is worn and has lots of piston ring blowby.

 

[Maclin]

DAng posting is hard for my PC for some reason, but add this... Could also be missing a baffle on the inside of the valve cover shielding the vent hole.

 

[johnzonh]

Hmmm interesting about the baffle. I will look at it. Gonna run a comp check too. The high oil makes sense. The engine was in 18 " of water over the winter because the noodle head never pulled the plug. Possible water seeped in? I was so thrilled when I got it because in the dead of winter the oil check was jet black. And yesterday it started right up! Then you could see a grown man cry when oil shoots out the top.

 

[Silvertip]

The first thing to check when this happens is to pull the dip stick and see how much oil (or milk shake) you have. If you have a milkshake it is going to be overfull. An engine sitting in 18 inches of water is also not a good idea.

 

[998cc]

Agreed. An engine sitting in water is not a good thing, but on the other hand, it may be a good thing in your case. If the water came into the block through the oil dipstick tube, as it did in my 165 inline 6, just drain and change the oil to see if the problem returns.

 

[johnzonh]

ok thanks guys. Instilling a bit more confidence in me! It was really reassuring to hear the engine ...it does sound rather nice! I rebuilt the carb... impeller...flushed the closed cooling (no loss in coolant over the winter..another good thing) replaced the thermostat..etc... (the guy had an automotive thermostat in it..no wonder it wasn't heating correctly) It was run in salt water over the years and nothing was flushed. I know it is a very controversial engine with the crank mounted alt. rotor and the overzealous fuel pump...but I hear all the time of guys who put time to take care of these really strong engines. Either you love 'em or hate 'em

 

[998cc]

Errant response--sorry guys.

 

[Maclin]

Is this a 165 I6? Or a 170 4 cylinder?

 

[johnzonh]

165 224 4 cyl. the bane of many a boater LOL

 

[johnzonh]

I wanted to clarify also..the sludge out the top was DEFINITELY aerated. it reminded me of those snakes you light for the fourth of july that look like..well ...cat terds

 

[Maclin]

When you described the charging system I had to ask, sounded like the 4 cyl 170/470/3.7lx. Those have a problem leaking antifreeze into the crankcase thru the front cam seals. There is a speedi-sleeve mod available to shore that up.

 

[johnzonh]

yeah I wish I could post a pic but this website has been giving me issues. Interesting about the seal..but so far I have been lucky with it. When I flushed the closed sytem and pulled apart the exchanger, I would guess it was only an inch down on antifreeze.. Not very thrilled to clean out the goop that shot out the top the other day. Reminded me of "attack of the killer tomatos". I closed up my cowl and just wanted to pretend it wasn't there. I know that the engine is very controversial because of the design and fuel pump issues and the direct drive rotor...but I also have found many others who have had really good luck with it, and have admired its torque. As soon as I get back home I will try to upload a few if you guys want.

 

[johnzonh]

well after finally getting home to take a look at things... problem was twofold. oil pan gasket has a slight leak..but even bigger issue was the riser gasket. Totally shot! made sense..since my coolant drained down to that point and I emptied a good 2 quarts of water out the bottom. No head damage...head gasket was ok and as far as I could tell..the riser, exhaust manifolds in good shape and the riser wasn't too bad as far as rust. Still serviceable. No bent rods... small amount of rust on the top 1/8 " of each cylinder . So there you go. New gaskets in on Monday, gonna check the decks and go from there Great thing is out of all that water and oil..@#$#@ thing still started right up. Good thing I ran it a whole 15 seconds.

 

[998cc]

Grrrreat! Glad to hear it.