Saltwater Contamination of Engine Oil - 6BY2-260

[fishheadbarandgrill]

You may remember that I mentioned on this forum that I was hit in the stern by a center console on plane in Januar. All the fiberglass repairs have been done and the system checks are just about complete. All that's really left is to replace the stern thruster (motor seized). The engine has been found to have saltwater contamination. First hint was visual check and I now have an oil analysis to confirm. Has anyone had similar oil contamination? The tech will start looking for the source of contamination next week and will start flushing the oil. I'm concerned that the saltwater contamination has been there since the "hit" on 25 January and may have caused enough damage to warrant a new/rebuilt engine. Thoughts?

 

[scross]

Stating the obvious here: A healthy, intact engine should not have salt water contamination in the engine oil. The logical assumption is that salt water contamination has been there since January. My advice is to document all of this! Keep some/all the oil pulled from the engine. Get written statements from the tech. Take lots of photos.
If it was my boat, I wouldn’t settle for anything but a replacement engine.

 

[BB marine]

First question is did you need to be towed when the accident happened? If so did you close the seacock valve for engine raw water cooling? If you did get towed and did not close the valve there is a chance that water could have entered the exhaust manifold and water ingested into the crankcase. If you didn't get towed disregard. Did the boat take on water during the incident or was the boat sitting below the water line when the boat hit your boat? These would be two other ways the water could have externally been injected into the engine through exhaust.

 

[scross]

Per Brian’s response about keeping the seacock closed when towing.
Here’s a 2016 reply to another related thread about water intrusion into an engine from Andrew Custis, “If a boat is being towed, it is common practice to shut the main engine seacock to prevent this from happening. On the bottom of the boats, we use a high speed pickup that is intended for boats that reach higher speeds to make sure the engines have enough water to cool them. It is possible that while towing without the seacock closed that water can fill up the muffler and get back into the motor.”
Andrew Custis
Ranger Tugs & Cutwater Boats
andrewcustis@rangertugs.com

In any event, I think the duration of having salt water inside the engine for several months now is the reason to ask for a replacement. Salt water rusting inside a sitting engine is a bad thing. Had the contamination been discovered immediately and addressed right away you might have been able to salvage the engine.

 

[tugnnaweigh]

Have you run the engine with the salty oil? Oil floats on water so in a perfect world the water entered and just went to and stayed on the bottom of the oil pan. Diesel engines that get completely submerged for example get “pickled” as part of the salvage, that is, fresh oil is pressured into every nook and cranny and then replaced again before restarting.

If the engine was operated with this salty oil replacement of the engine is the only way to avoid a endless series of failures and repairs. Likely insurance coverage will have guidelines as to what they're willing to do, also likely there’s gonna be a lot of finger pointing but there always is with insurance companies.

 

[NorthernFocus]

Have you run the engine with the salty oil? Oil floats on water so in a perfect world the water entered and just went to and stayed on the bottom of the oil pan....

That's a nice thought. Unfortunately if the water indeed got into the engine as a result of flooded exhaust during towing then it came in through the exhaust manifold, valves, and at least one cylinder. And having not been flushed for months now....

When engines get completely submerged it's actually not that bad if handled properly. For steel to rust(oxidize) it has to be exposed to oxygen. Which it's not while under water(unless it's there for years). The problems occur after it is recovered and exposed to air. If immediately flushed with fresh water, dried and oiled, no problem. Left sit for a few days before cleaning it up and it gets ugly.

 

[fishheadbarandgrill]

I don’t remember if I closed the seacock or not? At least I know where to steer the techs. I was towed for almost 9 hours to the closest boatyard. The engine has been run several times at the dock. Including the next day by the insurance surveyor. No issues on start up or at idle. Engine rpms always steady. Not sure if this indicates that water did not enter the cylinders or not.

 

[scross]

Bob,
If this were an airplane what you have is similar in significance to a prop strike. The only way at this point to know exactly how much damage has been done by the salt water is a complete engine tear down. A borescope inspection might give you some hints but a full engine tear down is the only way to know for sure exactly how much damage has been done. Engine tear downs are not cheap even before taking into consideration the cost of needed parts replacements.
Even though the engine seems to run normally now at low RPM, the damage done could lead to a catastrophic failure way before the normal “Time Before Overhaul” hours of a heathy engine. You don’t want to be out far from shore wondering when or if the engine is going to blow up.
If you ever decide to sell, the existing engine, if history fully disclosed, is a huge negative factor to resale value.
In my opinion you need a new engine. This accident was not your fault. Your boat needs to be restored to pre-collision condition!

 

[fishheadbarandgrill]

I appreciate everyone’s comments. While I’m anxious to get my boat back, it is much more important to get it repaired properly.

 

[knotflying]

I don’t remember if I closed the seacock or not? At least I know where to steer the techs. I was towed for almost 9 hours to the closest boatyard. The engine has been run several times at the dock. Including the next day by the insurance surveyor. No issues on start up or at idle. Engine rpms always steady. Not sure if this indicates that water did not enter the cylinders or not.

That does not necessarily mean sea water did not enter the engine while towing. There could have been enough to get in, but not enough to cause a hydro-lock. If I were a betting man I would say it was caused by the tow with an open sea cock.