Cooling System When it is necessary to open cooling system at radiator cap, shut off engine and remove fi ller cap only when cool enough to touch with bare hands. Slowly loosen cap to fi rst stop to relieve pressure before removing completely. This section covers operation and servicing of liquid cooling system. Cooling System Maintenance and Service Maintenance Maintaining correct coolant level, cleaning any debris accumulation from radiator surfaces, and insuring all parts are in proper operating condition, is critical to ensuring long life, proper system performance and preventing overheating.
To ensure proper air circulation, make sure radiator, cooling fan, drive belt, pulleys, cooling fi ns, and external surfaces of engine are kept clean and in good condition at all times. Check coolant level and clean away any debris accumulation daily or before each use. Simultaneously inspect hoses and all system connections for signs of leakage. Make sure cooling fan is not cracked or missing any blades. Check that fan belt and two drive pulleys, are in good condition and proper belt tension is present. Service Lift screen vertically to remove for cleaning/servicing. Clean screen and cooling fi ns of radiator with a soft brush or blow out using clean compressed air.
To avoid damage to screen and cooling fi ns, do not use a high pressure washer to clean. Cooling System Components Cooling system consists of these following components: ● Radiator with removable screen ● Hoses ● Coolant Pump and Belt ● Thermostat ● Intake Manifold with Thermostat Housing ● Radiator Cap ● Cooling Fan, Belt, and Drive Pulleys ● Overfl ow Reservoir ● Crankcase and Heads with Integral Cooling Passages Operation Engine coolant is pumped through cooling system by a pump, belt-driven off camshaft. Coolant coming out of pump is divided, and moves simultaneously through separate circuits within each head and corresponding sides of crankcase.
As coolant moves through these passages, it absorbs heat from engine parts. After traveling through engine, coolant from two separate circuits merges and moves through intake manifold to lower side of thermostat. During warm-up, thermostat is closed, preventing circulation through radiator. Coolant circulates through engine only and is returned to pump via bypass hose. When engine heat brings coolant up to a temperature of 79.4°C (175°F), thermostat will begin to open, allowing coolant to circulate through upper hose to radiator. Thermostat is completely open at 90.5°C (195°F) allowing full coolant fl ow through radiator, where it is cooled.
After getting cooled in radiator, coolant is drawn into pump through lower radiator hose and circulation starts all over again. A cooling fan, driven off fl ywheel by a belt, draws ambient air through radiator, to maintain cooling process. Coolant will provide protection from -37°C (-34°F) to 108°C (226°F). For protection and use outside indicated temperature limits, follow antifreeze manufacturer's instructions on container, but do not exceed 70% antifreeze. DO NOT use antifreeze with stop-leak additive(s), or put any other additives in cooling system. Checking Coolant Level Overfl ow Reservoir Details NOTE: Do not operate engine without coolant in system. Do not remove radiator cap when hot.
Engine coolant is hot and under pressure and can cause severe burns. To prevent engine overheating and damage, do not exceed more than 70% antifreeze in cooling system. Coolant level should be checked at overfl ow reservoir, located behind radiator on fan shroud. 1. Check coolant level within overfl ow reservoir. Coolant level should be between FULL and ADD marks on reservoir. Do not operate engine with coolant level below ADD mark. 38 66 690 01 Rev. C KohlerEngines.com WARNING Liquid coolant can get extremely hot from operation. Turning radiator cap when engine is hot can allow steam and scalding liquid to blow out and burn you severely. Shut off machine.
Only remove radiator cap when cool enough to touch with bare hands. Slowly loosen cap to fi rst stop to relieve pressure before removing completely. Hot liquid can cause severe burns. Do not loosen radiator cap while engine is operating or warm to touch. A B A Full B Add