Aftercooler Seawater side scale- how clean is clean?

[Robert McManus]

We have had the boat for one year. Bought it with 900 hours on 380hp QSB engines. Up to 1100 hrs now so we pulled starboard engine aftercooler to do clean and check, replace zincs, seals, etc.

Found some scale on seawater outlet side(bottom) of tube core. We soaked core tubes for about an hour in 1:10 mix of CLR and water. Cleaned up and rodded tubes with an aluminum rod and copper brush (for a 9mm firearm).

All tubes clear but there is still some scale visible on interior of seawater outlet end of tubes. Is this a significant amount or should we re-soak with CLR. Is there a point where CLR can start to deplete the core tube material? Vinegar?

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[john]

I use Castrol purple degreaser on the air side of the aftercooler to degrease it. Multiple times if they are sludged up. Then a little dawn soap. And pressure wash with a fan tip.

[Robert McManus]

Coolers clean and back in

We didn’t have any old wet suit foam pieces but I used a thin plastic sheet with a 6″hose clamp around the tube sheet to hold it in place. The “Barnacle Buster” worked in about 30 minutes to clean the internal tube surfaces.
The 2 cans of “Brake Clean” flushed a significant amount of oily residue that was not visible on the inlet side surface of the fins. If my ship is in port here next time I’ll bring them into work and drop them in the ultrasonic cleaner. We finished with a fresh water flush on the cores and reinstalled with the Alco Metalube as depicted in the SBMar video.

Hardest part of the job was getting at the outboard side of the port engine to remove the aftercooler.

[Rob Schepis]

After you pour the solution in you can put a heavy weight on the core to help seal the base to the foam pad, a 5lb pound plate or similar..

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Robert McManus

[Tony Athens]

Get a 8″ x 8″ piece of wet suit or refrigeration type foam about 1/2″ thick. Put it in the bottom of a 5 gallon bucket.

Stand your core on its end on the foam.. Steady it…….. Take about 4 ounces of common HCL pool acid–Add it to a quart of water… Fill up the core and let it bubble for 15-30 minutes– Now the “white crap” will be gone..

Tony.

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Robert McManus

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