Flush Cooling System

NOTE: 5320N block drain plug is located to the right of fuel pump.

For efficient operation, drain old coolant, flush the entire system, and fill with clean antifreeze solution at least once every two years.

causym CAUTION: DO NOT remove radiator cap or drain coolant until coolant is cold (temperature gauge should be below the green striped zone). Always loosen radiator cap or drain cock slowly to relieve any excess pressure.

1. Drain coolant - Remove radiator cap (A). Open drain valve (B) on radiator and drain coolant from radiator. Open block drain (C) and drain coolant from engine block:


A-Radiator Cap
B-Drain Valve
C-Block Drain

LV1911

5320N Shown

LV5089

5320N Shown

LV5090

5420N and 5520N Shown

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IMPORTANT: Thermostat must be removed to ensure a thorough flush.

2. Remove thermostat cover (A), remove thermostat, and install cover (without thermostat). Tighten cap screws to specification. (See Service section for procedure.)

Specification

Thermostat Cover Cap Screws -Torque 47 N·m (35 lb-ft)

3. Flush system with water - Close all drain valves/plugs and fill system with clean water. Run engine about 10 minutes to stir up possible rust or sediment. Stop engine and drain water from system before rust and sediment settle.

4. Flush system with radiator cleaner - Close all drain valve/plugs, reinstall coolant start aid switch, and fill the cooling system with a good commercial radiator cleaner and water. Follow instructions provided with cleaner. Stop engine and immediately drain system.

5. Flush system with water - Close all drain valves/plugs, reinstall coolant start aid switch, and fill with clean water to flush the system. Run the engine about 10 minutes, then drain out flushing water.

6. Replace thermostat - Remove thermostat cover (A) and clean off the gasket material. Apply gasket sealant to new gasket and install thermostat and cover. Tighten cap screws to specification. (See Service section for procedure.)

Specification

Thermostat Cover Cap Screws -Torque 47 N·m (35 lb-ft)

7. Fill with fresh coolant - Close all drain valves/plugs and fill with a mixture of antifreeze, soft water, and coolant conditioner as specified in the Fuels, Lubricants, and Coolant section.

LV5088

5420N and 5520N Shown


A-Thermostat Cover

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8. Check coolant level - Fill radiator to the top of the filler neck and fill the recovery tank to the LOW mark. Run the engine until operating temperature is reached. Let the engine cool (preferably overnight) and recheck the coolant level. Coolant level with a cold engine should be at the LOW mark. An engine at operating temperature should have a coolant level at the FULL mark. When filling the cooling system it may require several operating/cooling periods to stabilize the coolant level in the system. Add make-up coolant to the recovery tank as needed to bring the coolant level to the correct mark.

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