Closed Cooling System Heat Exchanger

[cmart]

I have a 1987 Four Winns with the 3.7L MerCruiser. I am in need of a Heat Exchanger. Please let me know where I may find one. I can't sink $1200 bucks into a new one.

Thanks.
Cory

 

[GA_Boater]

Ebay, Craig's List or a marine salvage yard. Or buy new.

Have you thought about repair? A radiator shop can repair a heat exchanger if they aren't too beat up.

 

[stonyloam]

What is wrong with yours?

 

[cmart]

I've thought about a radiator repair shop, but wasn't totally sure they could do it or not.

 

[cmart]

I've been losing coolant. Took it down to the head gasket last year and put a new gasket on it and had the head checked. Did the same thing the next time out.

I gave up after that and I now have it a repair shop and they pressure tested the exchanger and said that it's escaping through it.

What is wrong with yours?

 

[Scott Danforth]

where are you located? plenty of qualified radiator/boiler repair houses that deal with heat exchangers (look industrial, not automotive). Plenty of places to get your repaired. Ebay is also a wonderful option.

 

[philbullet]

I have one but it's a 3" ?

 

[Fun Times]

I have one but it's a 3" ?

please know that If there's any further interest in this at all by any party then please continue the conversations/transactions via private message only in order to stay within the forums guidelines....Thanks.

 

[cmart]

I'm in middle Tennessee.

where are you located? plenty of qualified radiator/boiler repair houses that deal with heat exchangers (look industrial, not automotive). Plenty of places to get your repaired. Ebay is also a wonderful option.

 

[stonyloam]

OK, sounds like you may have a leaking tube. Inside of your exchanger you have three sets of tubes that carry the raw cooling water. Raw water enters the front of the exchanger, flows back and forth three times and exits the back of the exchanger. If one of the tubes develops a leak you can lose antifreeze because the antifreeze is under higher pressure than the raw water. Now to the point, with both end caps removed you should be able to test each tube individually to see which is leaking. You can then simply plug both ends of the leaking tube and you should be OK. I think you can plug up to three tubes and still be OK, especially if you have a 4". A radiator shop should be able to solder in a plug, or JB Weld should work too, you could probably find a screw that is a close fit and epoxy it in. Anyway good luck!

 

[Scott Danforth]

the copper tubes are 0.248" OD tubes, with about a 0.020" wall. original construction was brazed double-sheet tube bundle,then brazed to the shell.

you could have a compromised tube, however most likely a tube sheet to shell crack. pull end caps, pressurize the glycol side to 15psi, spray soapy water and look for bubbles. The best way is to submerge in a light tank and look for an air stream.

JB weld will hold for about a week of thermal cycles then blow out

If it is a tube, a solder repair is fine for one to 3 tubes per pass. make sure to plug both ends of the tube. If you have more than 3 leaking tubes per pass, you get into velocity issues causing erosion.

If it is a shell to tube sheet crack, it will need to be re-brazed

Here is the results of a quick google search https://www.google.com/search?q=hea...1,1.4192109704358131&fz=10&qop=1&rlfi=hd:;si:

you want someone that has experience repairing a heat exchanger or industrial radiators.

 

[FreeBeeTony]

I had a similar problem last year.
​I was able to determine which tube was leaking and plugged it w/ JB Weld........held for at least 1/2 season and I intend on using it this season!