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Bertram31.com General Bulletin Board
Acid Flush a good Idea? *PIC*
Posted By: Sean Burlingham
Date: Friday, 29 April 2005, at 5:31 a.m.
After some research on boatdiesel.com and conversations with my diesel mechanic, I am planning to acid-flush my raw-water cooling systems this weekend. I’ve been nervous about sending muriatic acid through the raw-water engine intake, even though I got the advice that it was okay from several sources. Then I suddenly remembered to "check here first."
I’ve got CAT 3208T’s in my Bertram 33. They are not aftercooled, and the oil cooler AND trans oil cooler are both freshwater (I am told it is rare to have a fresh-water cooled tranny). So what we are talking about here are the water pump, heat exchangers, the exhaust, and the assorted hoses connecting them (am I missing anything?) I was told that in my case it was okay to do this because I don't have the aftercooler or the raw-water fed tranny cooler.
Anyway, the planned project is to temporarily remove the engine pencil zincs, pull the raw water intake hose off the sea strainer, and set it in a 5-gallon bucket filled with 50/50 solution of water and muriatic acid. Run the engine briefly to suck in the solution and then shut it off. Let the stuff fizz and eat whatever it finds for maybe 5-10 minutes while I re-connect the raw-water intake hose to the sea strainer, then run the engine again to flush the acid solution out the exhaust.
The reason for all this is that my heat exchanger/tank assembly is very difficult to remove. If I inserted the picture correctly (if so, note the fresh engine paint job my girlfriend did), you’ll see that the exchanger/tank assembly is located back behind a fixed portion of the engine covers with very little access (back behind the air cleaner). My mechanic said it colud not physically be removed without tearing open the engine box from the inside, which would be major ordeal. Being naturally stubborn, I set out to prove him wrong and spent many hours turning myself into a human pretzel, only to find out that the best that can be done is to remove the exchanger end caps and slide out the tube bundle, which only mostly comes out before it hits the hull. I rodded the tubes while I had access, and it was pretty clean anyway except for an old zinc from the previous owner that had fallen off inside the end cap and deposited some crusty stuff on a few of the tubes.
The hope is that with annual acid flushing such as descried above, I will be able to forestall indefinitely the need to remove the exchangers. Despite advice that it is okay, I am worried about acid sitting in the water pump (impeller and seal), in the exchanger body (solder joints), and through the rest of the raw water passages, even for a short while. Then I remembered to check here first.
Thanks in advance for any opinions. I’ve learned a great deal in a very short time from all the advice I’ve read on this board.
Sean
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