My first major problem with the Yanmar 6LP-STE

[Mike Ebert]

I thought this might help someone but I'm not sure how. Had to have some expensive repairs done and maybe there is a lesson here?

My cooling water level light came on while out fishing. No temp increase so we called it a day and headed in anyway. The Yanmar dealer is right next to my slip so I had the mechanic look for the reason the warning light came on. He pressure tested everything, filled the cooling water tank to the proper level and couldn't find any problem. He said just watch it and shut it down if it happens again.

The next weekend we headed out the Golden Gate and got halfway to the fishing grounds. Cooling water light comes on and now also the temp light. I shut it down and came in (after fishing) on the other engine. Call my mechanic for another look at it.

Pin hole leaks had developed in the exhaust manifold cooling jacket. What was a small hole turned into a line of big holes that leaked like a sieve. The cooling water went into the exhaust and then through the turbocharger and some into the oil system. When your mechanic calls to tell you the diagnosis and starts the conversation with "my condolences", you know it ain't good.

I needed a new manifold at $2460. The turbo was sent to a local turbo specialist and he estimated $2000 for a rebuild or $2400 for a new one. Went with the new one. Also an exhaust elbow which may have needed to be replaced anyway. With the labor, oil flushing, gaskets, etc. it totaled $9900.

When asked if I could have done something different, he said no, when the lights come on, you shut it down and look at it. This mechanic is very good and very fair with his billing so I have no gripe with him. He is trying to determine if the manifold had manufacturing defects or just let go after 13 years. He had never seen this problem before.

After the fix, both engines are running like a Swiss watch. And that's my story!

[jcollins]

Mike,
Thanks for sharing your story.

[OldDemps]

How many hours did you have on the engine?
Are the Zincs in that part of the cooling system?
Thanks

[jprohan]

13 years is a long time for an exhaust manifold; I would replace the other as well. There's an outfit in Ft. Lauderdale that makes a stainless "shower head" exhause elbow. It doesn't have the traditional little holes in a jacket around the manifold. Rather it introduces the cooling water via a hose (part of the salt water loop) as the exhause exits the manifold. The manifold itself is insulated; and the inch and a half "shower hole" will never clog.