bad exhaust=water in oil?

[MStokes]

Here is the problem...water in oil that builds quickly. Took head off, gasket fine and head flat, no cracks in head. Water even standing on one piston. Exhaust ports of head rusted and still damp, exhaust jacket on manifold full of water and rusty throughout. Also noticed that exhaust doesnt come out of prop when idling or revving on muffs, only through relief part. Now in one post I saw similiar to this, dsimpson said that a bad exhaust caused water in oil most of the time, not headgaskets. How could this be? What part could be bad and how could I check it?

 

[Bob_VT]

Re: bad exhaust=water in oil?

What motor, what outdrive and what kind of cooling system? Open or closed? I'm not an expert on I/O but rapidly (very rapidly!) learning.<br /><br />I just got my I/O book today on mercruisers and even the manuals are not too clear.<br /><br />Post the additional info under this same topic and you will get substantial response.<br /><br />Bob

 

[MStokes]

Re: bad exhaust=water in oil?

Oops, cant believe I did that! Anyway, it is an '89 GM 3.0 OMC Bayliner. Thanks..

 

[Walter]

Re: bad exhaust=water in oil?

Oh boy...here I go again...talking about something I know little about. Oh, what the heck...that's never stopped me before! Yours may be an OMC but I think the principle is about the same as my MerC.<br /><br />You still didn't say if it's fresh or closed cooling...so I'm gonna assume it's fresh.<br /><br />Inside the exhaust manifold are two chambers. One collects the exhaust (duh)...while water (for cooling) is constantly flowing through the other chamber. Should a crack develop in the wall between the chambers...water will leak into the engine via the head exhaust port when the engine is shut off. (Water is always present inside the manifold even with the engine off)<br /><br />This is exactly what happened to me...ended up costing me an engine. Ok, ok...I wanted a 350 anyway...but that's beside the point. Anyway...if you're certain the head is in good shape...the exhaust manifold should be your next prime suspect. I suppose your automotive type water pump could have a failed seal which might introduce water into the engine...but that's kinda rare. Usually, when that happens..it's the other way around. The higher oil pressure forces oil into your coolant.<br /><br />For what it's worth...<br /><br />Walt

 

[Trent]

Re: bad exhaust=water in oil?

Time to pull your manafolds and risers and have them pressure checked. A crack in one of these will lead to water in the oil. Keep running it this way and you will be buying a new engine.

 

[sea wolf]

Re: bad exhaust=water in oil?

do as trent says. i have the same engine & had the same problem you're having last season. i replaced manifold & elbow. problem solved. i also had the head magnafluxed & planed & i put in a new head gasket. if you're fairly handy with tools u can save the labor costs. cheaper than a new engine!

 

[MStokes]

Re: bad exhaust=water in oil?

Okay, I understand that a crack in the manifold could let water into the cylinders, but how does it get from there into the oil? Could it be the compression stroke forcing it past the rings when running? Duh...Idonknow.... Ohh, and what about the exhaust not coming through to the prop?<br />Anyway, I have the manifold and riser off. I will try to find a way to get them pressure checked and let you know.<br />One maybe crazy thought...why could you not run the coolant hose straight over the side somehow instead of into the manifold and through the exhaust? This would definitely eliminate and identify my problem if it is the manifold...hmm. Is it necessary for any reason to have the coolant exiting through the exhaust?

 

[Walter]

Re: bad exhaust=water in oil?

Crazy is one way of describing that idea. Truth is...it just won't work. Water flows through the manifold at all times to keep it cool. This is critical. You'll burn up that manifold in no time flat without water running through it.<br /><br />Walt

 

[flashback]

Re: bad exhaust=water in oil?

Mstokes, what happened? did you check the manifold?

 

[MStokes]

Re: bad exhaust=water in oil?

Alright, I finally got it ironed out. Ever find something and feel like an idiot because it was right there in front of you the whole time? Welll, thats me! As I sat and stared at the manifold (off the motor) I decided to try and fill up just the water passages with water using a funnel and a gallon of water. Its amazing how the water flow out of the exhaust ports could keep up with the amount I could pour in to the coolant hole (and yes, i was pouring it in the right hole!) So i guess it isnt much of a mystery how the water was getting in now. After a head job, new bearings, 1 new piston and all new gaskets it was the friggin manifold all along! If Ida only knew....<br />Anyway, one new manifold later and everything seems to be in top shape. Gonna try it out this weekend <crossing fingers> Whats it like to not have to drain the milkshake after every run on the lake?<br />Michael

 

[Trent]

Re: bad exhaust=water in oil?

Glad you found it! Hope you went ahead and changed the riser also? <br /><br />Tip: Water poured into the manafold will not always show where the leak is. Sometimes the crack only shows up after the engine heats up and lets the crack open up due to expanding of the metal. (Thats why you pressure check)<br /><br />Another trick is to pour gas (be careful) into the manafolds/risers. Gas will find its way to the cracks when water will not.