HELP Required ..Water in Oil,,..mercruiser 4.3

[spannerman]

The static water line is the water line when the boat is at rest, this is also how far up the exhaust pipes the water sits when the engine is not running. This is worked out by the boat builder in the design stage so that there is no danger of wave action causing water to enter the engine via the exhausts, and why some boats have riser extension kits because the engine sits very low in the hull so the aim is to create a high point that the water can't pass. Not an issue when the engine is running as the exhaust pressure blows the cooling water out.
If it starts and runs as well as you say then its very unlikely you have water in the cylinders, it could be that there is corrosion around one of the water passages between the head and block which then means there is no clamping effect on the metal insert in the head gasket and seawater can leak past the gasket.
If you take off the heads examine all the water passages to see if they are larger than the matching hole in the gasket. Another possibility is the inlet manifold gasket, they usually have some unused holes which are blanked off, if it perforates at one of these seawater can leak down into the cam shaft well between the banks.

 

[Col]

Another source of "water-in-oil" is the inlet manifold gaskets where the water crossover passages are.

You would need to take this off to do head gaskets so its worth inspecting old gaskets before taking heads right off.

FWIW I don't think the water in oil is related to the work you had done, other than maybe the increased water flow showing up an existing weakness.

 

[stevehamby1978]

I to am having this same issue with water in the oil on a 1987 Four Winns Horizon 170 with a 4.3 mercruiser engine. I contacted my local boat mechanic that had just replaced the flywheel. They had told me either a cracked block or bad head. After investigating and pulling the intake and the exhaust on the left side of the engine the only thing I found was the riser gasket is bad along with the riser bolts. Can this cause my oil to also overfill and become milky, tan color? I live in central Kansas and am only out on freshwater. There is no radiator or antifreeze on this boat it is only freshwater cooled. Thank you in advance for your response.

 

[davedpc]

I have the 4.3 turbo diesel 220 hp. which is indirectly cooled via a water to water and water to oil heat exchangers. The only mechanical damage I have had over 15 years was a rise in the oil level on one engine due to water ingress via a cracked cylinder head. I found that this was due to a casting fault and only became apparent after a overheat/plastic bag around the leg. The cylinder heads are individual and are cast alumilium .Get spares direct from VM 01246 455350 sometimes they have used parts.

 

[stevehamby1978]

I have the 4.3 turbo diesel 220 hp. which is indirectly cooled via a water to water and water to oil heat exchangers. The only mechanical damage I have had over 15 years was a rise in the oil level on one engine due to water ingress via a cracked cylinder head. I found that this was due to a casting fault and only became apparent after a overheat/plastic bag around the leg. The cylinder heads are individual and are cast alumilium .Get spares direct from VM 01246 455350 sometimes they have used parts.

My question is a little different I guess. can a bad exhaust riser gasket cause water to mix in with my oil? I found a bad exhaust riser gasket after my local boat dealer put in a new flywheel. I also pulled the intake off and there are no signs of cracks or a bad gasket so I am replacing the intake gaskets, the exhaust manifold gaskets, the exhaust riser gaskets, carb gaskets and t-stat gasket. My engine is just a water cooled 4.3 liter mercruiser engine.

 

[BruceK]

I would say possible but unlikely. The danger in a bad riser gasket leaking is getting water to leak back into the cylinders. You'd have had a much worse problem with hydraulic lock before the water reached the sump. Of course if you did get a mild hydraulic lock you might have blown the head gasket but imo I'd be looking at a cracked block / head gasket issue first. Where you are the winters can be quite severe, not performng good winterization and drying the block out has made cracked blocks a regular occurence. You might want to raise this issue on iboats.com http://forums.iboats.com/forum/engi...ance/mercruiser-i-o-inboard-engines-outdrives where this type of engine is discussed more frequently and subsequently more forumite knowlege in this genre. Good luck resolving the problem

 

[omega2]

From memory I believe the header tank and oil cooler are all one unit, and have heard of water/oil transfer going on in there, see if you can find PH MARINE somewhere in Berks 0r Hants, they may be able to assist, if it is that then it will not be a cheap fix.

This who you need?

http://www.phmarine.co.uk/