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Typical Cooling System Maintenance Schedules*


* Check owners manual for engine-specific information, including maximum engine-hours between service.

  OPEN-COOLED GAS
(FRESH WATER)
CLOSE-COOLED
GAS (SALT WATER)
CLOSE-COOLED DIESEL
(SALT WATER)
Rubber Raw-Water Impeller Every year; two at most Every year; two at most Every year; two at most
Bronze Raw-Water Impeller n/a n/a At overhaul or if leaking
Raw-Water Pump Rebuild At overhaul or if leaking At overhaul or if leaking At overhaul or if leaking
Circulating Pump Every few years or if leaking At overhaul or if leaking At overhaul or if leaking
Heat Exchanger n/a Every three years Every two years**
Thermostat Every few years or if sticking At overhaul At overhaul
Oil Cooler Check for obstructions or leaks at springtime launch When heat exchanger is cleaned When heat exchanger is cleaned
Transmission Oil Cooler Check for obstructions or leaks at springtime launch When heat exchanger is cleaned When heat exchanger is cleaned
Antifreeze-Cooled Charge-Air Cooler n/a n/a Every two years or 2,000 hours
Raw-Water-Cooled Charge-Air Cooler n/a n/a Every two years or 2,000 hours
Engine Zincs Check every Spring—more often for boats kept on shore power Check every 30 days and replace when 50% eroded Check every 30 days and replace when 50% eroded
Belts Every year; two at most Every year; two at most Every year; two at most

** With new lightweight aluminum heat-exchanger and charge-air cooler housings, timely maintenance is key to longevity.

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