Preventative Maintenance Cooling System

My engine has been running perfectly in the warm 80 degree Florida waters. But in preparation for an extended summer cruise I ran Barnacle Buster through the raw water cooling system for two hours. Think I’m glad I did. The bucket got green really fast. And then it just kept getting darker.

Periodic treatment of your cooling system with Barnacle Buster is a good approach. But don't forget servicing of your after cooler which requires removal and disassembly.

Also BB and similar are mildly corrosive to the marine metals in your cooling syste so I wouldn't want to do it yearly. Every 3-5 years should be ok.

David

The best preventative maintenance I can recommend for your raw water cooling system is regular freshwater flushing (if possible after each run, in a perfect world). Doing this will help greatly in reducing the ravages of "marine age" (saltwater damage over time).
Running things like Barnacle Buster through your system are a temporary "band aid" at best and cannot take the place of proper "off engine" servicing. All of your components should be removed from the engine for a proper cleaning (rodding out, removal of debris like impeller bits, pieces of anode, shells, and an acid cleaning if needed). All components should be pressure tested to ensure that the various products (liquids) stay where they are supposed to stay. For example we don't want our transmission fluid to leak out (or be diluted) with the exhaust seawater. Your aftercooler is especially in need of a regular off engine service. Not only do you need to ensure the raw water tubes are clear, but the air side "collects" oily gunk and needs a cleaning so that your engine receives a good air supply. These aftercoolers are basically a collection of dissimilar metals in an electrolyte (saltwater) and corrosion can occur very quickly. If left even a bit too long, the aftercooler can suffer unrepairable damage requiring replacement. Plus, the only thing keeping saltwater out of your engine are 2 rubber "O" rings and a smooth mating surface that can be subject to corrosion.
Tony Athens, a marine diesel expert, recommends servicing your aftercooler "off engine" every 3 years, and all other components (fuel cooler, gear oil cooler, and heat exchanger) every 5-6 years. Your anti-freeze, pressure cap, and theromostat can all be replaced at this time (as PM) to keep things running cool.
Don't forget your exhaust elbow, especially if it is a Cummins OEM double jacketed elbow. When these start to leak (internally and not visible from the outside), they can allow saltwater to get into the turbo (ruining it) and possibly into the exhaust manifold of the engine doing expensive damage. Tony calls this "setup" "doomed to fail".

Check out his website sbmar.com under both Tony's Tips and the various forums for more great info on this and other subjects.

I see Tony's Tips has Jeff Cote from Pacific Yacht Systems doing the video for the freshwater flush setup.
https://www.sbmar.com/articles/the-benefits-of-fresh-water-flushing-your-marine-diesel-engine/

Too funny Steve

Don't forget the coolant side can cause heating problems and requires flushing every few years, just like a car. When I had a yard, I fixed a lot of heating problems caused on the coolant side after others threw parts and money at the raw water side.

I recently did a complete disassembly and flush of all the raw water parts of my two CAT 3208TA cooling systems. Other than some corrosion on the outside of the heat exchangers due to salt water leaks, there was zero visible corrosion on any of the rest of the raw water parts. They all looked like new inside after 29 years of use. I think the parts are made of bronze and seem oblivious to salt water. Is that typical?



FWIW, in my experience, a tiny amount of organic growth will dramatically darken Barnacle Buster, but the color does not seem to affect the effectiveness of BB at all. I have two gallons that I have been using, then filtering, and using again for 3 years. Paint filters from an auto parts store work great for this.

If you were able to go 29 years without any issues, that is FANTASTIC. Not something I would recommend to anyone though.
Corrosion can and often does occur inside these components and internal leaks can develop. Gear oil coolers can fail and dump all of the transmission oil and fill the tranny with seawater. Saltwater can leak into the coolant (engine) side of the system doing internal engine damage, etc. A leaking aftercooler can send seawater spray (or more) into the intake side of the engine causing huge damage over time. Or, these problems can just lead to an overheat, and that alone can cause major damage.
Personally, for a few hours of my time and a few dollars, I would regularly take these components apart, replace seals, O rings, etc., properly clean (the air side of the aftercooler can only be cleaned when taken apart), and pressure test to ensure that my system works and continues to work trouble free.
Tony Athens has photos of many failed components (failed) due to owner neglect, resulting in major expenses that could have been avoided.
Again, good on you that it worked out well. Maybe the components used by CAT are just really good, well engineered, quality products???

Cast bronze components stand up very well to salt water. It is the aluminum in the shell of after coolers and sometimes exhaust manifolds that doesn't like salt water or even engine coolant very well.

Yanmar aluminum exhaust manifolds can develop pin holes particularly if the wrong antifreeze is used where combustion detonations start a tiny corrosion spot that grows. After coolers are notorious for corrosion that usually starts on the air side, but gets salt spray etc inside which eats at the o ring seal and can eventually break through to the raw water side with sometimes disastrous results.

Of all the metals used in boat systems these are the best to the worst, well more or less:

titanium
bronze
316 stainless steel
cast iron
aluminum
steel

David

firehoser75 said:

If you were able to go 29 years without any issues, that is FANTASTIC. Not something I would recommend to anyone though.
Corrosion can and often does occur inside these components and internal leaks can develop. Gear oil coolers can fail and dump all of the transmission oil and fill the tranny with seawater. Saltwater can leak into the coolant (engine) side of the system doing internal engine damage, etc. A leaking aftercooler can send seawater spray (or more) into the intake side of the engine causing huge damage over time. Or, these problems can just lead to an overheat, and that alone can cause major damage.
Personally, for a few hours of my time and a few dollars, I would regularly take these components apart, replace seals, O rings, etc., properly clean (the air side of the aftercooler can only be cleaned when taken apart), and pressure test to ensure that my system works and continues to work trouble free.
Tony Athens has photos of many failed components (failed) due to owner neglect, resulting in major expenses that could have been avoided.
Again, good on you that it worked out well. Maybe the components used by CAT are just really good, well engineered, quality products???

Click to expand...

I never meant to imply the cooling system had not been serviced in 29 years, just that when I serviced the 29 year old parts, they looked great. The most impressive piece of the cooling system is the transmission oil cooler, it is incredibly robust and the bronze casting that makes up the bulk of it has to weigh at least 10 lbs. The flat plate that covers the back of the casting and forms the bracket that holds it on the engine is 5/8" thick steel and it's all bolted together (with a thin bronze plate in between to keep the sea water from the steel) like it's made to withstand 1000 psi.