Seawater system descaling
Marine engine cooling system maintenance should be performed every 2 years or 500 hours. The seawater side of your cooling system is where annual maintenance is critical.
Back in the day, it wasn’t uncommon to remove the heat exchanger every couple of years and send it off to the local automotive radiator repair shop to get it acid-dipped and boiled out thoroughly to clean out all the deposits.
1.Check for seawater circulation exiting the engine exhaust whenever the engine is running. Note that in some cases this may not occur until the engine reaches operating temperature.
2.Check coolant level before starting engine each time.
3.Check and replace the seawater pump impeller every 250 hours, or seasonally.
4.Replace engine cooling system seawater anodes annually.
5.Clean cooling system seawater passages at least every two years or 500 hours.
Unfortunately, there are draw backs to this amazing supply of unlimited cool water. Because heat exchangers run at such hot temperatures, the metals are continually expanding and shrinking. This means surfaces don’t last forever, and O-rings and seals will need to be changed regularly.
People don’t use their boat as regularly as a car, and often skip routine maintenance “because it hasn’t been used”. This isn’t justifiable in the saltwater environment. Once you get a leaking O-ring, you have introduced salt-water to the exterior of your engine. Slowly but surely, it starts to corrode away anything in its path, and even damages the cooling component sealing surfaces. Meaning when you service the components, you will start to find throw-away items instead of just O-rings that require replacement. The last consideration is sacrificial anodes – if the engines aren’t getting serviced, the anodes definitely aren’t getting changed. Simply put, anodes are designed in the cooling system to corrode away (sacrificial) before any of the more expensive components.
