3406 MARINE ENGINE Cooling System Caterpillar

The water temperature gauge should normally register in the NORMAL range when operating. However, with some systems, as long as the coolant does not boil the cooling system is functioning properly.

1. Check the water temperature gauge reading frequently during operation. Note any deviation from the usual reading. Have repairs made as needed.

2. If the water temperature gauge continually registers near - or in the "HOT" range - without boiling, have the gauge checked to determine if the cooling system is functioning properly. Have repairs made as needed.

Checking Coolant Level

With the engine stopped:

1. Slowly turn the filler cap to the first stop and release pressure.

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Be careful. If the engine is warm - steam may spray outward under high pressure.

2. Push the cap down; turn until the cap is released.

3. Maintain coolant level to the base of the fill pipe.

4. Make-up coolant should be one of the following, in the order of preference:

a. Permanent antifreeze and fresh water solution.

b. Drinkable water and rust inhibitor solution.

c. Drinkable water.

d. Any available fresh water.

(a) Must be used if engine is to be shut down in below freezing weather without draining the coolant. (b) Can only be used when the coolant temperature is above freezing, or if the coolant will be immediately drained after shut down during below freezing temperatures.

(c) or (d) Should only be used as a "temporary fix". As soon as possible, return the system to either (a) or (b).

Draining Radiator

If a permanent antifreeze solution is used in the cooling system, either renew the rust inhibitor every three months by adding AVSpare Corrosion Inhibitor, or drain and replace the solution yearly.

Whenever it is necessary to drain the cooling system:

1. Shut off the engine.

2. Slowly turn the pressure cap until the cap is released.

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Be careful. If the engine is warm - steam may spray outward under high pressure.

3. Open the drain valve on the radiator.

Draining Engine Jacket Water

1. Drain the radiator.

2. Drain the oil cooler and water pump line.

3. Remove the engine block drain plug.

Draining Marine Engine Jacket Water

1. Shut the engine off.

2. Slowly turn the pressure cap to the first stop and release pressure.

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Be careful. If the engine is warm-steam may spray outward under high pressure.

3. Push the cap down and turn until the cap is released.

4. Remove the water pump drain plug.

5. Remove the engine block drain plug.

6. Remove the water cooled manifold drain plug.

Draining Sea Water System

If ambient temperature may go below freezing, drain the sea water line between the heat exchanger and the sea water pump.

1. Loosen the hose clamps and hose, or remove the drain plug if so equipped.

2. Remove the cover from the sea water pump.

Filling Cooling System

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NOTICE

When filling a cooling system, it is essential air pockets within the system are able to vent to the atmosphere. Air trapped in the system can cause major engine problems.

1. Use water that is low in scale forming minerals. Do not use softened water.

2. While filling the cooling system, stop the filling procedure several times to allow the coolant level to stabilize and expel air from the system.

3. Add coolant until the coolant level reaches the base of the fill pipe. Allow space for coolant expansion.

4. Start the engine and allow it to idle several minutes with the filler cap off. Add coolant as necessary.

5. Install the filler cap.

6. Check the system for leaks. Have the engine cooling system repaired if necessary.

Cleaning Cooling System

To clean the cooling system, any good commercial radiator cleaning solution can be used. Follow the instructions included with the cleaner.

The cooling system can be cleaned using oxalic acid and sodium carbonate as follows:

1. Fill the cooling system with a solution of 2 pounds of oxalic acid or sodium bisulphate (NaHSO₄) with every 10 gallons of water (mix 25 grams per liter of water).

2. Start the engine and operate at operating temperatures for 1/2 to 1 hour.

3. Stop the engine and drain the cooling system.

4. Flush the system with clean water until the draining water is clear.

5. Install all drain plugs.

6. Fill with a solution consisting of 1/2 pound of sodium carbonate crystals (Na₂CO₃) with every 10 gallons of water (mix 6 grams per liter of water.)

7. Start and run the engine for 10 minutes.

8. Stop the engine and drain the cooling system.

9. Flush the cooling system with clean water.

10. Install all drain plugs.

Zinc Rods
(Salt Water Operations Only)

Salt water has a highly corrosive reaction with metal by a chemical action called "electrolysis". To prevent this chemical action taking place with parts used in the sea water system, zinc plugs are placed in the sea water piping. Zinc is a relatively soft metal which reacts quite readily with the salt water. Thus, by the deterioration of the zinc, the sea water system parts are protected from corrosion.

The zinc rods must be inspected regularly and be replaced as they become deteriorated. The zinc rod plugs are painted red for easy identification.

Inspecting Zinc Rods

1. Move the governor control lever to the shut-off position.

2. Remove and inspect all of the zinc plugs. They are painted red for easy identification. Depending upon the engine, their location may be in the oil cooler heat exchanger bonnet, sea water heat exchanger bonnet, aftercooler lines, sea water pump, or in the sea water lines.

3. Tap the zinc rods lightly with a hammer.

4. Inspect the rods. If a rod has deteriorated, or flakes apart when tapped, install a new zinc rod.

Installing a New Zinc Rod

1. Unscrew or drill the existing rod from the plug base.

2. Install a new rod in the plug base.

3. Install the plug.

Alternator-Fan Belts

Checking Belt Condition and Tension

1. Check belts for excess wear, fraying and cracking.

NOTE: When belt replacement is necessary, belts must be replaced in complete matched sets. Never replace a single belt as the new belt will carry all of the load and fail rapidly.

2. Apply a 25 pound (10 kg) force perpendicular to the belt, midway between the driver and driven pulley. Belt deflection should be 9/16" to 13/16" (15-20 mm). Adjust the belt tension as required.

Adjusting Alternator Belts:

1. Loosen the locknut on the belt tightener rod.

2. Turn the adjustment nut until correct belt deflection is obtained.

3. Tighten the locknut.

4. Check the belt adjustment.

Adjusting Fan Belts

1. Loosen the four mounting bolts.

2. Turn the adjusting bolt until correct belt tension is obtained.

3. Tighten the four mounting bolts.

4. Check the belt adjustment.

Lubricating Fan Drive

Lubricate the fan drive bearing; 1 or 2 strokes, 1 fitting.

Sea Water System

Sea Water Strainer

Periodically inspect the sea water strainer for plugging. The period for inspection will depend upon the cleanliness and depth of the water. The strainer must be clean to allow proper cooling of the engine.

1. Remove the sea water strainer.

2. Clean the screen of dirt and debris.

3. Install the strainer.

4. Fill the strainer and pump suction line with water to ensure proper priming of the system.

Sea Water Pump

All sea water pumps require periodic maintenance. The interval for maintenance will depend upon the cleanliness and depth of the water in which the vessel is operated. The pump must be serviced more frequently if the vessel is operated in shallow water where sand and sediment are present, than where deep, clear water is present.

Sand and debris will eventually damage the rubber impeller blades. The pump cover should be removed and the impeller blades inspected at least once a year; more frequently in sand conditions.

If the raw water system was drained either for storage purposes or for repairs made to the engine or vessel; or for allowing inspection of the impeller blades:

1. Remove the sea water pump cover.

2. Remove the plate.

3. Inspect the impeller blades for cracks or breaks. Install a new impeller if blade failures are observed.

4. Squeeze, or flow, hand cleaner or liquid detergent between the impeller blades. Do not use a cleaner which contains grit. The purpose of the cleaner is to lubricate the impeller blades before water is drawn into the pump housing.

5. Install the plate.

6. Inspect the gasket on the cover. If necessary, install a new gasket.

7. Install the cover.

8. Vent and fill the sea water suction line.