Barnacle Buster

I had the ac guy run that through my ac system. He found a pin hole leak in one of the older compressors. The evidence was BB spraying all over my generator room and into my open tool box drawers(I was in the process of organizing them). It took him two hours to clean up the mess. I still find evidence of the event. One was the plastic fresh water shut off valve to the forward head. Luckily I was in the room when the housing developed a leak. I though I had and accident as it was spraying my back side while at work in that room, no lie.

DON'T, you do not want that stuff circulating through a CAT aftercooler. Doing stuff like this is probably why CAT aftercoolers are failing. Do it proper and pull the aftercoolers and heat exchangers. Barnacle Buster generally works a lot of times, but it's really a bandaid. It doesn't get all of the shells or zincs out that are stuck in heat exchangers, is tough on metals as it all doesn't get out a lot of times, and the entire reason for pulling coolers is so you can physically inspect them and see what they look like and pressure test them.

I would tend to second that advice but also if one did use the BB could one not use some sodium bicarbonate to circulate through the system to neutralize the acid?

How about flushing with 2500 gallons of sea water? Turn the key and go for a ride.

How about taking the heat exchangers apart and off of the boat for a professional cleaning, inspection, and test like the manufacturers engineers recommend in the owners manual?

Snarky snarky. OK, I should have been more specific as in that I was not recommending this to OP. It was a comment on the idea of neutralizing acid in a system that processes hundreds of gallons of water a minute. Yes, following manufacturers is generally not a bad idea.

Hmmm a no-brainer. The maintenance schedules are written to protect the Mfg'r during warranty's. Such as Cat's 2 yr aftercooler schedule and short 6 yr replacement period. Not saying pulling, cleaning , and testing may not be necessary, but only if you are under warranty. Their plate heat exchanger's only need inspection, only pulled if issues found, and can be cleaned in place too. Plumbing a freshwater flush system for you engine raw water side while sitting at the dock will extend those maintenance items.

Happy to use the “come to your dock” BB cleaning service.
I got 5 heat exchangers and hate to pull ‘em all just to do a proper acid boil, an inspection, a paint job and a re-instal.
Paid $500 for the 2 hour treatment.
Yes, the BB burns the zincs, but do it at the same time the zincs are due for replacements anyway.
Clean looking air cooler 16 months after the BB treatment:

THIS. You're talking about an engine with KNOWN aftercooler failures, and CAT's recommendation became that of replacing them every 6 years, just a few years ago, when the C18 has been in service since 2004,and trying to compare it to a commercial rated heavy duty engine???

Yeah well, reading comprehension is everything. The OP is asking about a set of Caterpillar C18's, not 3512's not megayachts.........

I've used BB on my boats , both Detroit Diesels, with success. BUT both boats being used, after purchase I always pull all the coolers first to see what's really going on and get them cleaned, inspected, pressure tested by my shop here at home. Now that I've got clean equipment , I will help keep them clear with and occasional soak of BB.

If it's a new boat to you and you are not positively sure the last time they were pulled and inspected, do it the right way pull them get them checked and cleaned.