Engines

Jul 6, 2010
28
Catalina 30 Bainbridge Island, WA
Has anyone tried Barnacle Buster to clean out the heat exchanger?
Thanks in advance,
Tom
 
Feb 2, 2014
29
Catalina 30 mkII Pasadena, MD
I used muriatic acid from Home Depot/Lowes for about $8.00 for one gallon of the concentrated stuff (about 4 years ago, so it may be a little more now). Use rubber gloves and consider a respirator (I did it outside and when the wind shifted I held my breath because that stuff is very strong). It cleaned out my heat exchanger in no time and I only used half a gallon. I took the heat exchanger off the boat and removed the end caps to pour the acid through the inside of the tubes and poured it into the fresh water inlet and outlet and then the coolant inlet/outlet. Its been 4 years and it is still flowing well.
 

SG

.
Feb 11, 2017
1,670
J/Boat J/160 Annapolis
Careful. If you had some aluminum (for example Yanmar) you will end you messing it up.

I’d suggest you take the part to a radiator shop. Have the uktrasonically clean it. That does a lot better job.
 
Jul 6, 2010
28
Catalina 30 Bainbridge Island, WA
I used muriatic acid from Home Depot/Lowes for about $8.00 for one gallon of the concentrated stuff (about 4 years ago, so it may be a little more now). Use rubber gloves and consider a respirator (I did it outside and when the wind shifted I held my breath because that stuff is very strong). It cleaned out my heat exchanger in no time and I only used half a gallon. I took the heat exchanger off the boat and removed the end caps to pour the acid through the inside of the tubes and poured it into the fresh water inlet and outlet and then the coolant inlet/outlet. Its been 4 years and it is still flowing well.
 
Jul 6, 2010
28
Catalina 30 Bainbridge Island, WA
Thanks for the tip on muriatic acid. Did you soak the HE in a bucket or just pour the muriatic acid into the tubes?
Tom
 

RitSim

.
Jan 29, 2018
406
Beneteau 411 Branford
I have done this. This is for a copper type exchanger not aluminum. Make a solution of acid/water- no need to use bottle concentration. Add acid SLOWLY with stirring to the water - Do not add water to acid. Wear goggles you can't get to the water faucet fast enough if it splatters, wear gloves.
Add the exchanger to the solution and it will bubble till there is no acid available or no crud on your exchanger. The waste solution can be neutralized with baking soda. The neutral solution is mostly salt water.
 
Jul 23, 2009
857
Beneteau 31 Oceanis Grand Lake, Oklahoma
I have successfully used oxalic acid followed by sodium carbonate. General Motors has a TSB that can be found on the web explaining the process. I did it on a 90s 30KW John Deere powered generator that I was having overheating problems with. I tried several auto parts store flushes on it, they helped but did not solve the overheating. I was sure the radiator had more deposits in it so I hunted down the chemicals, wood bleach and washing soda, and gave it a try. I drained lots of chunky green and the orange water form that cooling system. It hasn't overheated sense.

I wouldn't be afraid to try it on a boat. Be sure to read the TSB. The sodium carbonate is rough on aluminum so don't use too much or run it too long. I ran it 2hrs with the acid and 20min with base.

It just occurred to me that you are probably trying to clear the raw water side of the heat exchanger. This might still be worth a try but you will have modify the method.

The green fluid is oxilac acid flush.
The orange is the sodium carbonate flush.
The brown is the parts store flush that I tried twice before.

Note, the pictures are name incorrectly. Sorry about that.
 

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SG

.
Feb 11, 2017
1,670
J/Boat J/160 Annapolis
Uncle Steve says: go to an automotive Radiator shop. Have them overnight clean it with an Ultrasonic cleaner. Will cost you less. Do the pros use muriatic or other acids to clean their radiators (aka heat exchangers)? Why should you?

I had Hinckley try to use chemicals years ago. It didn't do the job. After Two and a half weeks, they sent the part out and, overnight it was fixed. The coating on the copper isn't aparent. The ultrasonic process really cleans it. The acid is either not effective -- or mor likely, in harsh concentrations to cause damage.
 
Jul 23, 2009
857
Beneteau 31 Oceanis Grand Lake, Oklahoma
The pros used to "hot tank" radiators. Good chance it was an acid. I think the EPA, or some other government agency, put a stop to this.

SG does make a good point. If the heat exchanger is easily removed, take it to a pro. Couldn't be too expensive. I used chemicals because the radiator was going to be difficult to remove and the site would be without backup power while I had it apart.
 
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Jul 6, 2010
28
Catalina 30 Bainbridge Island, WA
Thanks for all your replies. After taking off the end caps of the heat exchanger, I found one inlet was blocked with hard packed salt. After chipping away at it with a small screwdriver, I was able to free up the blockage.
Will paint it, install new zinc before putt it back on engine. I was able to check small tubes by inserting welding rod thru them.
Thanks, Tom
 
Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
Tom. Best to try and pressure test before re installing. You have to systems. The raw water and the coolant side. Each should be pressurized to assure no leaks occur between them or out of the Heat Exchanger. Then you can install with confidence. Most radiator shops can run a test for you. Maybe $20 at most. Cash. Better now then to discover after you have reinstalled that there is a coolant leak running out the exhaust.
 
Jul 6, 2010
28
Catalina 30 Bainbridge Island, WA
Tom. Best to try and pressure test before re installing. You have to systems. The raw water and the coolant side. Each should be pressurized to assure no leaks occur between them or out of the Heat Exchanger. Then you can install with confidence. Most radiator shops can run a test for you. Maybe $20 at most. Cash. Better now then to discover after you have reinstalled that there is a coolant leak running out the exhaust.