Symptoms point to a possible Mixing Elbow problem on my Yanmar ('83 H34) and was hoping for an easy tip to remove that thing. There is not enough room in there for a large pipe wrench to get a good bite and it is not moving with anything I have been able to try. If the elbow is my problem, can the rust be cleaned out of there, or do I have to get a new one? Thanks, Bruce CATWALK (H34)
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Elbow Removal
Bruce, I assume your Yanmar is a 3GM30F engine, if so it is probably better to remove the elbow and exhaust manifold in one piece and fix it on the bench, this ususall avoids damaging the manifold. The part in between the elbow and the manifold is a stainless steel coupler that has a left hand thread on one end and a right hand thread on the other, so make sure you are turning it the correct way. I would suggest that you replace the elbow and coupler and assemble with anti seize compound as it will make replacement eaiser next time. As for cleaning out the elbow, I have never seen one that was not worn out inside. The cost of a replacement is not too bad so changing it is the way to go. Good luck Gerald S/V "Defender"
Bruce, I assume your Yanmar is a 3GM30F engine, if so it is probably better to remove the elbow and exhaust manifold in one piece and fix it on the bench, this ususall avoids damaging the manifold. The part in between the elbow and the manifold is a stainless steel coupler that has a left hand thread on one end and a right hand thread on the other, so make sure you are turning it the correct way. I would suggest that you replace the elbow and coupler and assemble with anti seize compound as it will make replacement eaiser next time. As for cleaning out the elbow, I have never seen one that was not worn out inside. The cost of a replacement is not too bad so changing it is the way to go. Good luck Gerald S/V "Defender"
Not that difficult
Bruce: It is not that difficult. You may wish you had one more hand, but it can be done. I posted this a couple of years ago when I did mine. Be sure that you have all of the parts that you need including a new gasket and maybe a dab of gasket sealant. My elbow was very difficult to seperate from the exhaust manifold because of rust. It took a torch, vise and a breaker bar with a large pipe wrench. You may want to take it home and do the disassembly and reassembly.
Bruce: It is not that difficult. You may wish you had one more hand, but it can be done. I posted this a couple of years ago when I did mine. Be sure that you have all of the parts that you need including a new gasket and maybe a dab of gasket sealant. My elbow was very difficult to seperate from the exhaust manifold because of rust. It took a torch, vise and a breaker bar with a large pipe wrench. You may want to take it home and do the disassembly and reassembly.
Exhaust elbow -- Thanks Steve D.
Thanks a lot for the advice on the elbow. I got mine off and as suspected the rust had closed off the water entry. Not as expected was just how solidly it was sealed! I wonder if there is any way to avoid the rust buildup on a new one. One of my symptoms, along with being hard to start, overheating, and no water coming out of the exhaust, was the disappearance of engine anti-freeze. Do you think the buildup of heat or exhaust pressure (where WAS it going?) could have blown the head gasket? If so, any idea what kind of job that may be? Thanks again, Bruce
Thanks a lot for the advice on the elbow. I got mine off and as suspected the rust had closed off the water entry. Not as expected was just how solidly it was sealed! I wonder if there is any way to avoid the rust buildup on a new one. One of my symptoms, along with being hard to start, overheating, and no water coming out of the exhaust, was the disappearance of engine anti-freeze. Do you think the buildup of heat or exhaust pressure (where WAS it going?) could have blown the head gasket? If so, any idea what kind of job that may be? Thanks again, Bruce
It was suggested to me that I paint the inside
with some kind of high temperature paint. The other part of that idea was to put a y valve on the intake side of the raw cooling pump. Then I could run fresh water into the engine each time I use the engine just before I shut it off. That would keep the salt water flushed out of the engine - not sitting in the raw water passages. I think the whole plan included painting the inside of all of the areas where raw water would pass. I do not personaly know of anyone who has actually done this but my surveyer said that he saw this on another boat he looked at. I made my replacement elbow with black pipe from HomeDepot instead. It will cost me about $10 to replace the elbow on an annual basis. Kind of like an oil change...
with some kind of high temperature paint. The other part of that idea was to put a y valve on the intake side of the raw cooling pump. Then I could run fresh water into the engine each time I use the engine just before I shut it off. That would keep the salt water flushed out of the engine - not sitting in the raw water passages. I think the whole plan included painting the inside of all of the areas where raw water would pass. I do not personaly know of anyone who has actually done this but my surveyer said that he saw this on another boat he looked at. I made my replacement elbow with black pipe from HomeDepot instead. It will cost me about $10 to replace the elbow on an annual basis. Kind of like an oil change...
Patrick,
can you post a new, updated picture of your homemade elbow? I didn't save your old one, sorry. Bruce, I had my NEW elbow ceramic coated. It's on my web site. I also installed a fresh water flush system to help the elbow. And it only helps the elbow. If you track down the inner working of your Yanmar heat exchange system, you will find that you don't even have a zinc installed. You don't need one for the same reason you don't need a fresh water flush. There are no corrosive or non compatible metals in your engine. Only the elbow is a stinker. See photo #6 on my web site. P.S. The loss of antifreeze is another stinker. How much did you lose over what length of time? That's not good but the head gasket can be replaced in about 4 hours. You can do it your self.
can you post a new, updated picture of your homemade elbow? I didn't save your old one, sorry. Bruce, I had my NEW elbow ceramic coated. It's on my web site. I also installed a fresh water flush system to help the elbow. And it only helps the elbow. If you track down the inner working of your Yanmar heat exchange system, you will find that you don't even have a zinc installed. You don't need one for the same reason you don't need a fresh water flush. There are no corrosive or non compatible metals in your engine. Only the elbow is a stinker. See photo #6 on my web site. P.S. The loss of antifreeze is another stinker. How much did you lose over what length of time? That's not good but the head gasket can be replaced in about 4 hours. You can do it your self.
Cleaning Exhaust Elbow
I cleaned my exhaust elbow with muriatic acid full strength, which can be purchased at Home Depot, ect for about $5/gallon. Acid cleaned out all of the interior plugged elbow down to shiny metal (did not seem to eat any into the metal itself). Left the elbow over night in a bucket. This acid creates very noxious fumes so keep it outside. Worked for me relatively easily once I got the elbow off.
I cleaned my exhaust elbow with muriatic acid full strength, which can be purchased at Home Depot, ect for about $5/gallon. Acid cleaned out all of the interior plugged elbow down to shiny metal (did not seem to eat any into the metal itself). Left the elbow over night in a bucket. This acid creates very noxious fumes so keep it outside. Worked for me relatively easily once I got the elbow off.
Shoulda coulda
Seems I should have read this post too Symptoms are similar to Heat exchanger thread Seems I should have read this post too Symptoms are similar to Heat exchanger thread I have already removed my MIXING elbow; exhaust elbow and joint as one. The 4 bolts were relatively easy to remove. My reason was the right/left hand thd connector was loose, I took it to a shop that has a Hydraulic press to hold onto it so I could tighten with a LARGE pipe wrench. I have not reinstalled it yet as I was preparing to solve the next issue, Loss of coolant. I am going to check the 3/8 elbow again seems to me I blew through it and it was clear but now I not sure Thanks
Seems I should have read this post too Symptoms are similar to Heat exchanger thread Seems I should have read this post too Symptoms are similar to Heat exchanger thread I have already removed my MIXING elbow; exhaust elbow and joint as one. The 4 bolts were relatively easy to remove. My reason was the right/left hand thd connector was loose, I took it to a shop that has a Hydraulic press to hold onto it so I could tighten with a LARGE pipe wrench. I have not reinstalled it yet as I was preparing to solve the next issue, Loss of coolant. I am going to check the 3/8 elbow again seems to me I blew through it and it was clear but now I not sure Thanks
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