Leaking heat exchanger-weld or replace?

[fliti]

We sprung a pinprick leak in the outer casing of the heat exchanger on our 10-year old, 1100 hours Yanmar 100 HP 4JH3-HTE. Plugged it temporarily with JB Weld which saw us through the season but now need to get it properly fixed. There are two options-remove and weld the existing casing and if the remaining parts pass muster, stick it back on or sling the whole thing and replace. The bill for the parts for the latter looks like over £3000! Does any one out there have direct experience of the welding option and how did it work out?

 

[Heckler]

We sprung a pinprick leak in the outer casing of the heat exchanger on our 10-year old, 1100 hours Yanmar 100 HP 4JH3-HTE. Plugged it temporarily with JB Weld which saw us through the season but now need to get it properly fixed. There are two options-remove and weld the existing casing and if the remaining parts pass muster, stick it back on or sling the whole thing and replace. The bill for the parts for the latter looks like over £3000! Does any one out there have direct experience of the welding option and how did it work out?

The issue is going to be how many other pinpricks are waiting to show themselves. I would take it apart, inspect it and then make a considered decision. If as I suspect it is made of brass or bronze then silver soldering is an option, very do it youselfish!
If a new one then look at a few issues ago of PBO where a contributor used a standard heat exchanger, ASAP sell them, they are a fraction of the cost of OEM stuff. BUT and it is a big BUT, you do need a modicum of skills to do this!
Stu

 

[cliff]

Weld it up or should I say have it welded up by someone who knows what they are doing. Forget "Fred in his shed" down the road or any of the bodgers on here.

 

[Heckler]

Weld it up or should I say have it welded up by someone who knows what they are doing. Forget "Fred in his shed" down the road or any of the bodgers on here.

Are you referring to me as fred in his shed?
Stu

 

[cliff]

Are you referring to me as fred in his shed?
Stu

No. but you do know the type - got a Clarke type MIG machine and can stick a couple of bits of angle iron together and thinks he is a welder

 

[Heckler]

No. but you do know the type - got a Clarke type MIG machine and can stick a couple of bits of angle iron together and thinks he is a welder

Good!
Stu

 

[cliff]

Good!
Stu

????

 

[Birdseye]

We sprung a pinprick leak in the outer casing of the heat exchanger on our 10-year old, 1100 hours Yanmar 100 HP 4JH3-HTE. Plugged it temporarily with JB Weld which saw us through the season but now need to get it properly fixed. There are two options-remove and weld the existing casing and if the remaining parts pass muster, stick it back on or sling the whole thing and replace. The bill for the parts for the latter looks like over £3000! Does any one out there have direct experience of the welding option and how did it work out?

This might sound like an odd suggestion but I discovered when I had bought my current boat 4 years ago that at some time previously the owner had repaired the heat exchanger stack where the tubes joined the end plate with epoxy. I thought "this wont last" but it has done with no problems at all. Then I remembered a pullover on which I had got some west epoxy whilst installing an engine in my first boat some 25 years ago. That epoxy is still there despite the best efforts of SWMBO and her washing machine.

Not clear form this first post whether you have a split in a cast iron outer of in the brass tube stack. Cast iron can be welded successfully but it isnt a job for the guy at the local garage and his mig set. The brass bit can be soldered to repair.

 

[coopec]

You haven't told us what it is made of

T
If a new one then look at a few issues ago of PBO where a contributor used a standard heat exchanger, ASAP sell them, they are a fraction of the cost of OEM stuff. BUT and it is a big BUT, you do need a modicum of skills to do this!
Stu

Heat exchangers are used on heavy machines (dozers, graders, loaders etc) so you might pick up one seconhand from that industry