[jclark003]

Barnacle buster is a mild acid solution that is designed to clean the sea water side of aftercooler, oil coolers and heat exchangers. I've never used it but understand it is quite popular with salt water crowd. What it won't do is clean the air side of the aftercooler which eventually gets impregnated with oil from CCV and such, degrading the charge air cooling capability.

I am surprised cummins recommended this as well. Assuming many years in salt, unless they were previously serviced they are probably way overdue to be removed, cleaned and pressure tested. A leaking AC can destroy an engine quite quickly and salt water is no friend to raw water cooled ACs. Freshwater use is another story and the service interval can be extended.

One test for the air side is the measure the difference between sea water temp and manifold/charge air temperature. If I'm not mistaken the manifold temp should be around 5-10 degrees hotter than sea water. The forums on boatdiesel.com or the guys at seaboard marine are quite knowledgeable and can help you make a more informed decision.

Best of luck