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34
Operation Section
Cold Weather Operation
In cold weather, check the coolant often for the
correct glycol concentration in order to ensure
adequate freeze protection.
Engine Block Heaters
Engine block heaters (if equipped) heat the
engine jacket water that surrounds the combustion
chambers. This provides the following functions:
•
Startability is improved.
•
Warm up time is reduced.
An electric block heater can be activated once
the engine is stopped. An effective block heater
is typically a 1250/1500 W unit. Consult your
Perkins dealer or your Perkins distributor for more
information.
Idling the Engine
When idling after the engine is started in cold
weather, increase the engine rpm from 1000 to 1200
rpm. This 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 82 °C (179.6 °F).
Recommendations for Coolant
Warm Up
Warm up an engine that has cooled below normal
operating temperatures due to inactivity. This 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
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 completely burned
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 the engine is started and the engine is stopped
many times without being operated in order to warm
up completely, the carbon deposits become thicker.
This can cause the following problems:
This document is printed from SPI². Not for Resale.
•
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 71 °C (160 °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.
In addition, the engine must be thoroughly warmed in
order to keep other engine parts in better condition
and 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 will provide
longer service life for the engine bearings, the piston
rings, and other parts. However, limit unnecessary
idle time to ten 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
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 ensures maximum coolant flow to
the radiator in order to achieve maximum heat
dissipation.
Note: 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.
SEBU7833-03
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