Preventive Maintenance Engine Cooling System
Medium Duty
(R10/06) Y53-6008 – 147 –
8. Idle the engine until it reaches normal operating temper-
ature.
9. Fill the radiator as necessary to raise the coolant level to
the proper reading. Replace the surge tank pressure
cap.
Engine (Block) Heater (option)
WARNING! Do not use the heater if there are any
signs of problems. Engine block heaters can
cause fires resulting in serious personal injury
and/or property damage if not properly main-
tained and operated. Regularly inspect the
engine block heater wiring and connector for
damaged or frayed wires. Contact your Autho-
rized Service Center or the manufacturer of the
heater if you are in need of repairs or informa-
tion.
CAUTION: Always unplug the block heater
before starting your engine. Damage to the cool-
ing system could occur if not turned OFF
(unplugged).
Use a solution of half ethylene glycol antifreeze and half
water for best heater performance. Do not use more than 65
percent concentration of antifreeze, as a shortened heater
life will result.
After servicing the cooling system, operate the vehicle for a
day or two before using the heater. Trapped air inside the
engine needs time to escape.
