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MAINTENANCE Raw Water Cooling System Drain at the end of each boating season.
If the cooling system is protected by a coolant filter/conditioner, the element should be replaced every 150 hours or annually, whichever comes first.
Sea Strainers Inspect sea strainers daily. Clean sea strainers at least annually. Clean more often if surface seaweed growth or water contamination levels are fairly high. COOLANT CONDITIONER CHANGE 23
When changing the coolant conditioner, shut the engine OFF. Keep the engine stop control in the OFF position. To avoid injury when removing the heat exchanger cap, turn the cap counterclockwise to the first stop. DO NOT depress the heat exchanger cap until the pressure has dissipated. After all pressure has completely dissipated, press the cap downward and continue turning to remove. To install a new coolant conditioner: 1. Relieve cooling system pressure by removing the heat exchanger cap. 2. Using tool J 29927, or equivalent, remove the coolant conditioner. 3. Clean the coolant conditioner mounting surface.
Figure 23 — Coolant Conditioner
Coolant Filter/Conditioners are used in the M-E7 marine engines to filter impurities such as scale or sand from the coolant. Filter elements are treated with chemicals that soften coolant water, minimize scale deposits, maintain an acid-free environment and act as a rust preventive. Coolant filter/conditioner elements should be replaced every 150 hours or annually, preferably at the beginning of the boating season. Correct coolant conditioning must be maintained to provide maximum engine block and cylinder sleeve protection. On wet sleeve engines, a minimum nitrite level of 1200 ppm and a minimum pH of 8.5 is required. Changing the coolant conditioner at the specified 150-hour intervals ensures that the proper level of protection is maintained in the cooling system. Coolant conditioners contain a reduced solids chemical inhibitor package that allows coolant conditioner change intervals to coincide with the recommended oil change intervals.
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4. Apply a light film of engine oil to the sealing gasket of the replacement coolant conditioner. 5. Install the new coolant conditioner until the gasket contacts the base and then tighten an additional 1/2 to 3/4 turn. 6. Reinstall the heat exchanger cap. Start the engine and check for leaks. 7. Replenish the cooling system with the proper mixture of coolant as necessary.
