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58
Operation Section
Cold Weather Operation
Engine Block Heaters
Engine block heaters (if equipped) heat the engine
jacket water that surrounds the combustion
chambers. This heat provides the following functions:
• Startability is improved.
• Warm up time is reduced.
An electric block heater can be activated once the
engine is stopped. A block heater can be 110 V dc or
240 V dc. The output can be 750/1000W. Consult
your Perkins distributor for more information.
Idling the Engine
After starting the engine, the engine speed will be
held at low speed. The time held at low speed will
depend on ambient temperature and time since last
run. The procedure is in order to allow the engine
system to stabilize. When idling after the engine is
started in cold weather, increase the engine rpm from
1000 to 1200 rpm. This idling will warm up the engine
more quickly. Maintaining an elevated low idle speed
for extended periods will be easier with the
installation of a hand throttle. The engine should not
be "raced" in order to speed up the warm-up process.
While the engine is idling, the application of a light
load (parasitic load) will assist in achieving the
minimum operating temperature. The minimum
operating temperature is 80° C (176° F).
Recommendations for Coolant
Warm Up
Warm up an engine that has cooled below normal
operating temperatures due to inactivity. This warm
-up should be performed before the engine is
returned to full operation. During operation in very
cold temperature conditions, damage to engine valve
mechanisms can result from engine operation for
short intervals. This damage can happen if the
engine is started and the engine is stopped many
times without being operated in order to warm up
completely.
When the engine is operated below normal operating
temperatures, fuel and oil are not burned completely
in the combustion chamber. This fuel and oil causes
soft carbon deposits to form on the valve stems.
Generally, the deposits do not cause problems and
the deposits are burned off during operation at
normal engine operating temperatures.
When starting and stopping an engine many times
without being operated in order to warm up
completely, the carbon deposits become thicker. This
starting and stopping can cause the following
problems:
• Free operation of the valves is prevented.
• Valves become stuck.
• Pushrods may become bent.
• Other damage to valve train components can
result.
For this reason, when the engine is started, the
engine must be operated until the coolant
temperature is 80° C (176° F) minimum. Carbon
deposits on the valve stems will be kept at a
minimum and the free operation of the valves and the
valve components will be maintained.
The engine must be thoroughly warmed in order to
keep other engine parts in better condition. The
service life of the engine will be generally extended.
Lubrication will be improved. There will be less acid
and less sludge in the oil. This condition will provide
longer service life for the engine bearings, the piston
rings, and other parts. However, limit unnecessary
idle time to 10 minutes in order to reduce wear and
unnecessary fuel consumption.
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.
SEBU9068-03
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