Liquid Cooled Vertical Crankshaft Service Manual

7.1
Section 7
Cooling System
7
Section 7
Cooling System
WARNING: Explosive release of fluids from pressurized cooling system can cause serious burns!
When it is necessary to open cooling system at radiator cap, shut off engine and remove filler cap only when
cool enough to touch with bare hands. Slowly loosen cap to first stop to relieve pressure before removing
completely.
LV560, LV625, LV675
This section covers the operation and servicing of the
liquid cooling system.
Cooling System Components
The cooling system consists of the following
components:
• Patented Circular Radiator
• Hoses
• Patented Coolant Pump with Rubber Drive Belt
• Thermostat
• Intake Manifold with Thermostat Housing
• Radiator Cap
• Radial Cooling Fan
• Overflow Reservoir
• Crankcase and Heads with Integral Cooling
Passages
Operation
The engine coolant is pumped through the cooling
system by a pump, belt-driven off the camshaft. The
coolant coming out of the pump is divided, and moves
simultaneously through separate parallel circuits within
each head and the corresponding sides of the
crankcase. As the coolant moves through these
passages in the engine, it absorbs heat from the
engine parts. After traveling through the engine, the
coolant from the two separate circuits is united and
moves through the intake manifold to the lower side of
the thermostat. During warm-up, the thermostat is
closed, preventing circulation through the radiators.
The coolant circulates through the engine only and is
returned to the pump via the bypass hose. When
engine heat brings the coolant up to a temperature of
79.4º C (175º F), the thermostat will begin to open,
allowing coolant to circulate through the radiators. The
thermostat is completely open at 90.5º C (195º F),
allowing full coolant flow through the radiators. The
rotation of the cooling fan, attached to the flywheel,
draws in ambient air and blows it through the radiators
to carry away the heat being dissipated from the
coolant. After getting ‘‘cooled’’ in the radiator, the
coolant is drawn into the pump from the hoses
connected to the bottom of each of the radiators and
circulation starts all over again.
Figure 7-1. Cooling System.
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