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70
Cold Weather Operation
Radiator Restrictions
The Water Temperature Regulator and
Insulated Heater Lines
The engine is equipped with a water temperature
regulator. When the engine coolant is below the
correct operating temperature, jacket water circulates
through the engine cylinder block and into the engine
cylinder head. The coolant then returns to the cylinder
block via an internal passage that bypasses the valve
of the coolant temperature regulator. This return
ensures that coolant flows around the engine under
cold operating conditions. The water temperature
regulator begins to open when the engine jacket
water has reached the correct minimum operating
temperature. As the jacket water coolant temperature
rises above the minimum operating temperature, the
water temperature regulator opens further allowing
more coolant through the radiator to dissipate excess
heat.
The progressive opening of the water temperature
regulator operates the progressive closing of the
bypass passage between the cylinder block and
head. This action ensures maximum coolant flow to
the radiator in order to achieve maximum heat
dissipation.
Note: Do not restrict the air flow. Restriction of the air
flow can damage the fuel system. Perkins
discourages the use of all air flow restriction devices
such as radiator shutters. Restriction of the air flow
can result in the following: high exhaust
temperatures, power loss, excessive fan usage and
reduction in fuel economy.
A cab heater is beneficial in very cold weather. The
feed from the engine and the return lines from the cab
should be insulated in order to reduce heat loss to the
outside air.
Recommendation for Crankcase Breather
Protection
Crankcase ventilation gases contain a large quantity
of water vapor. This water vapor can freeze in cold
ambient conditions and can plug or damage the
crankcase ventilation system. If the engine is
operated in temperatures below −25° C (−13° F),
measures must be taken to prevent freezing and
plugging of the breather system. An open breather
system will operate more effectively in temperatures
below −25° C (−13° F). In extreme weather
conditions insulating the breather hose will help to
protect the system.
Consult with your Perkins dealer or your Perkins
distributer for the recommended breather
components for operation from −25° to -40°C
(−13° to -72.°F).
Radiator Restrictions
Perkins discourages the use of airflow restriction
devices that are mounted in front of radiators. Airflow
restriction can cause the following conditions:
• High exhaust temperatures
• Power loss
• Excessive fan usage
• Reduction in fuel economy
Reducing air flow over components will also affect
under hood temperatures. Reducing air flow can
increase surface temperatures during an
aftertreatment regeneration and could affect
component reliability.
Reducing air flow can increase surface temperatures
during an aftertreatment regeneration and could
affect component reliability.
If an airflow restriction device must be used, the
device should have a permanent opening directly in
line with the fan hub. The device must have a
minimum opening dimension of at least 770 cm
(120 in
2
).
A centered opening that is directly in line with the fan
hub is specified in order to prevent an interrupted
airflow on the fan blades. Interrupted airflow on the
fan blades could cause a fan failure.
Perkins recommends a warning device for the inlet
manifold temperature and/or the installation of an inlet
air temperature gauge. The warning device for the
inlet manifold temperature should be set at 75 °C
(167 °F). The inlet manifold air temperature should
not exceed 75 °C (167 °F). Temperatures that
exceed this limit can cause power loss and potential
engine damage.
Fuel and the Effect from Cold
Weather
Note: Only use grades of fuel that are recommended
by Perkins . Refer to this Operation and Maintenance
Manual, "Fluid Recommendations".
The following components provide a means of
minimizing problems in cold weather:
SEBU8732
i05203509
2
i02685960
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