Milky oil, 7.4 Merc
 

Hey Guys...

I have a 2000 7.4 Merc. MPI. I did an oil change to start off my season this year and noticed a bit of a milky color to the oil. I did an oil change and it was still there but seemed to be less (or so I hope). I changed it again and there is still a trace. No water is getting to cylinders and she seems to be running strong. In my mind there can only be a couple of things that could cause water in crank case and not up top.

First off is the one I dont want to hear and that is a cracked water jacket in block.

Second I thought maybe oil cooler but wouldnt I then also see oil in exhaust water. I changed the cooler once a few years ago cause oil was spewing out of my exhaust.

Third I guess could be a head gasket or manifold problem but wouldnt I then also have water in cylinders?

My first thought was that it is just condensation but then wouldnt 2 oil changes take care of that. So far I have only run her on ear muffs this year.

Engine has a lot of hours on it and owes me nothing... I am thinking that if this is something major then I am just gonna run it till it blows up then go for repower next year.

Your thoughts much appreciated.

Thanks

fixx
 

if i were to guess first check the 4 corners of the 8 intake bolts to see if they are loose,,take a wrench and tighten them..my second guess would be the oil cooler and yes their should be some oil in the water when fired..it eill leak into the oil system when the engine is off then mix when the engine is fired.
if its a salt water engine then i would tear the engine down and inspect..

reveresion?

There is definitely no oil coming out of the exhaust... I had this happen a few years ago and it was the oil cooler. I guess there is no way that a problem in the cooler would only leak water into the oil system without also leaking oil out of the exhaust right? I will take a wrench to those bolts and see... I did the whole top end (form the heads up) two years ago and maybe they loosened themselves up.

Thank you for your help.

I dont think so... I have only run her this year on a hose. Everything seems to be flowing properly... put in a new raw water pump. I think this is either easy as an oil cooler or loose bolt or it's gonna be a bad one.

Thanks also

only on a hose so far this year. you didn't get all the water out. you can never get it all. it will boil out when oil gets hot enough, can't do that in driveway. use it. if it starts getting worse, you neeed to worry. but you mentioned 1500 hours salt raw water cooling in another thread. someday in forseeable future, you will need to worry...

Of course... and I know that. I also said that the motor owes me nothing. I am just trying to save the inevitable for as long as possible! If this not an easy fix I am just going to run it til it blows up. Thank god for Sea Tow!!!

Have you ruled out leaky exhaust risers (or elbows)... Cylinders 4 and 5 take the beating the worst with leaking stock exhaust. If the plugs in those holes have signs of rust, that may be your problem.

No water is getting to any of the cylinders at all! That would be easy. I have a feeling that I am dealing with some nasty condensation since my boat sat in the boat yard all last season... and winter before that was brutal!!! It was winterized good and all wrapped up but it must have really built up. Now as earlier said I need to really heat the motor up to boil the water off. We'll see.

Thanks for your input though.