Yanmar Exhaust Manifold / Heat Exchanger Corrosion

[sabray]

Cummins 4b3.3. No pics but great gear.you asked.

[delmarrey]

Originally Posted by Maxs

Delmarrey, did you installed the zincs already?? I have a 3jh4e, and I'm planning to install a zinc plug in the front cooler cap... Any toughts??

Thanks for reminding me. I need to get it on my list. Right now it's flooded in fresh water, so no concerns. I flush the motor with fresh water if I let it sit for more then a week. But when I start the Trans Pac it'll be on my maintenance list. Tomorrow I'll start the research.

[Maxs]

This yanmar will be installed in a couple of months. Right know I have a Universal M30, which, just like you, I flush with fresh water after every use, but still, I have to replace the heat exchanger zinc every six months. That's why I'm planning to install the zinc in the yanmar before it goes into the boat. I guess that the cooler cap will be the right place to install a plug with a zinc. I can't see a reason of why it won't work in that location. The best thing is that I won't even have to mess with the manifold. Just take the cap to a shop in order to drill a hole and weld a female threaded fitting for the plug.

[rebel heart]

Got a pm from a marine deisel guy who said he would pick Perkins over Yanmar, but that's honestly the first time I've heard that. So factor that in that a smart pro mechanic out there thinks differently than other smart pro mechanics.

[dandrews]

Originally Posted by rebel heart

Got a pm from a marine deisel guy who said he would pick Perkins over Yanmar, but that's honestly the first time I've heard that. So factor that in that a smart pro mechanic out there thinks differently than other smart pro mechanics.

LOL Rebel...you mean there can be different opinions on boating issues.

Don

[sabray]

Alright . Why would you not choose a low rpm naturally aspirated diesel like a cummins or beta.
Parts? My cummins is the standard for small diesels world wide. No issue getting parts. Pay less if parts are needed. So far I only have had to replace filters.one if the many well researched choices I made. Yanmar may be a industry standard. Given all the exhaust issues etc... That are a standard complaint I will take my cummins.

[rebel heart]

By "exhaust issues" you mean I needed to replace my elbow after ten years?

[sabray]

Rebel you asked? Look for issues with yanmar. ...... Surprise. A high rpm turbo charged diesal is high on issues. The exhaust elbow is well known issue with yanmars. I'll take my low rpm naturally aspirated cummins. Just saying. You got the best gear you have. I have a cummins. Nah nah nah. So your expert that had an idea might have a point.

[DeepFrz]

We have seen a lot of fuel injection problems, fuel pump failures, injector problems and loss of compression issues this year on this site. Also what appear to be turbo problems. Some of these have been very difficult to pinpoint and have cost members a lot of money.

[Charlie]

I have a Yanmar 4JH4E. I found a bunch of rust under the exhaust manifold 8 months ago. I spent two days removing the motor mount, the engine mount (that attaches to the motor mount), the gear shift lever on the transmission. I cleaned everything up repainted and tightened up the hose clamps for all of the hoses. Now some of those parts are rusted again. Yesterday I went and looked at a different boat that had a 4JH4 TE and saw that that boat had a similar problem though not as bad as mine. Does anyone know the cause of this. I have looked at the engine when idling and it doesn't seem to leak. I guess there could be a leak under load or at a higher RPM but I would have to sit in a lazaret to see it.

[Maxs]

A friends 3jh4e leaks under pressure through the Coolant drain on the manifold, right above the port engine mount... Everything in that location was rusted because of it...

[Charlie]

Thanks Max I will look at that. It is a likely suspect.

[lateral]

If any one knows of a source for stock, heavier, 3GM30F elbows, I need a spare for backup. I would prefer if the inner pipe was a little longer.
Cheers

[lateral]

Originally Posted by Maxs

A friends 3jh4e leaks under pressure through the Coolant drain on the manifold, right above the port engine mount... Everything in that location was rusted because of it...

From the tap or where it screws into manifold? That shouldn't be a hard fix.

I think my 3Gm30F has weeped raw water from the exhaust elbow/ manifold heat exchanger gasket from day one . 'Cos there was a lot of corrosion in the area on the side of the block/mount same place as your friends.
I also had to have the end of manifold/elbow machined flat to take the new gasket @ only 500hrs. Otherwise its the devil I know.

[cfarrar]

I was thinking of replacing my 4JH3 exhaust elbow as preventative maintenance. Is it just the elbow itself - that rusty cast iron elbow and the gasket? Anything else I should replace while I'm at it?