heat exchanger repair

[theboyner]

Yo, first time virgin but have enjoyed the quality of threads i have been reading.
If anyone has done this in a home shop please pitch in.
Can a 4" heat exchanger be repaired. steps or process would be welcome. Tks theboyner

 

[Bt Doctur]

Re: heat exchanger repair

for what application , what type of repair

 

[theboyner]

Re: heat exchanger repair

for what application , what type of repair

The engine is a merc cruiser 3.7l. Like a dolt i believe i left some water in the exchanger over what was an unseasonably cold winter and froze the exchanger. Air tested it and we seem to have crossover air from one line to the next, suggesting breakage inside the exchanger. I would like to remove the core and disassemble to the degree where i can replace the broken pipe lines,but, am stuck.Tks.

 

[stonyloam]

Re: heat exchanger repair

The engine is a merc cruiser 3.7l. Like a dolt i believe i left some water in the exchanger over what was an unseasonably cold winter and froze the exchanger. Air tested it and we seem to have crossover air from one line to the next, suggesting breakage inside the exchanger. I would like to remove the core and disassemble to the degree where i can replace the broken pipe lines,but, am stuck.Tks.

I am not sure that you can take the core out, and to have someone do it would probably cost more than a new one. If you can isolate the leakage to one or two tubes you might be able to block them off and still have enough cooling capacity. The raw water flows through the tubes, so if you take the end caps off you should be able to determine which are leaking by putting air in one end of the tube and blocking the other. Good luck.

 

[theboyner]

Re: heat exchanger repair

I am not sure that you can take the core out, and to have someone do it would probably cost more than a new one. If you can isolate the leakage to one or two tubes you might be able to block them off and still have enough cooling capacity. The raw water flows through the tubes, so if you take the end caps off you should be able to determine which are leaking by putting air in one end of the tube and blocking the other. Good luck.

Thanks for the participation but we have already tried this and determined that a number of them are leaking air during the test, however, i was under the impression that the coolant flowed through the tubes and the raw water through the cannister. Will have to dbl check that. I appreciate the suggestions. Next step is to drill the ends of the ones we have identified as leaking, extract them, and replace them with copper or brass lines. which ever i can find in this remote part of the world. I will take pics and post if we decide to do this. Thanks again. TheBoyner

 

[Don S]

Re: heat exchanger repair

I think you are going to be surprised to find out there are supports and baffles inside the heat exchanger that supports the tube bundle and directs water flow. Here is a site that shows what I mean better than I can explain it. http://rotunds.com/Heat Exchanger.html

 

[theboyner]

Re: heat exchanger repair

Hi Don.
More info than this poor brain can handle, but it did help in that now i know i have a tube and shell type.Theboyner Do you know in the unit in question, are the tubes connected to the baffle plates inside the shell or just at the ends, so if i drill them to disconnect each end will this work ? will they release so i can install new tubes. theboyner

 

[Don S]

Re: heat exchanger repair

Have no clue, never took one apart. Volvo uses tube bundle inserts (as they call them) for oil and water cooling in their diesels. Even short ones have the diverter/baffles. And they are all soldered together. You wouldn't want things moving around and rubbing on each other and causing a leak.
Basically, I'm just warning you that you are probably not going to drill each end and remove the tube and replace it. The radiator shops that I have used for repairs, usually just block off one or two tubes that may be leaking. More than that, and you may get overheating for lack of flow.
This picture shows how your raw water section flows from end to end in sever passes before it exits out the exhaust.

 

[theboyner]

Re: heat exchanger repair

Thanks Don. I think we agree that trying to re-build one of these is Gods work not mine. Just on the off chance, Princess Auto is advertising a 6", 11 tube OIL cooler. These things are somewhat Generic, are they not. As long as inlet and outlet ports are effective and there is sufficient capacity, should one not be able to accomodate a swap? By the way does anyone know what the Gallon Per Minute flow rate is for the original? Obviously i am thrashing around for a replacement or repair technique which i can function with some hope of success short of buying a very expensive replacement.Thanks again.

 

[stonyloam]

Re: heat exchanger repair

Yeah the raw water flows through the tubes, otherwise there would be no way to clean the raw water side should the need arise. I seriously doubt that the oil cooler could give anywhere near the cooling capacity that you need. Think of it this way, you need at least the same cooling capacity as the radiator in your car, probably more. The only thing they talk about in the manual is blocking off the bad tubes.

 

[Scott Danforth]

Re: heat exchanger repair

having worked for a company that made marine heat exchangers, I can only say, it is much cheaper and easier to buy a new one than try to remake them.

most of the tubes are either brazed or crimped to the baffles. all the tubes are brazed to the headers, then the whole bundle is installed in the shell, brazed, and then the end caps are brazed in.

And no, there is no way an 11 tube oil cooler will work. the factory 4" oil cooler has about 225 1/4" tubes in it, and a bunch of baffles.

The factory oil cooler was made by either Champ (now Alfa Laval Champ), Sen-Dure, or Monitor (all in Florida) - The heat exchanger is a commodity. there area a few will-fitters, and many commercial radiator shops that will pressure test and repair heat exchangers (or replace by buying from one of the manufacturers)

 

[a1nowell]

Re: heat exchanger repair

theboyner,
Welcome, since you have a M/C 470, 3.7L engine you need to be aware of this website, www.breezeworks.net . It's a 470 only site and has many parts new and used. If you going to get another heat exchanger make sure you are getting the 4" heat exchanger. Also try ebay.

Good Luck,

Larry

 

[theboyner]

Re: heat exchanger repair

Larry, Scott Stoney and Don as well as all the rest who participated...all great info gentlemen.I have learned to buy not try, so thanks.