Operating the Engine Operating Instructions
– 62 – Y53-6008
Medium Duty (R10/06)
• Use a solution of half ethylene glycol antifreeze and half
water for best heater performance. Do not exceed 60
percent concentration of antifreeze, as it can shorten
heater life. See page 146
for more information.
• 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.
Cold Weather Starting—Air Intake Heater
Do not use ether or any other starting fluid as a cold starting
aid in your Medium Duty. Engine conditions are automatically
monitored and in cold weather the fuel/air mixture is pre-
heated in the manifold.
WARNING! Do not use ether or other starting flu-
ids as a cold-starting aid in your Medium Duty.
Your engine uses either an electrical grid or an
open flame inside the manifold, to heat the air/
fuel mixture for cold weather starting. If ether or
another starting fluid is used, the air/fuel will
ignite inside the manifold, which could cause an
explosion and severe injury.
With each engine make, the air intake heating system works
differently. To understand fully how your engine's heating sys-
tem operates, see the engine Operation and Maintenance
Manual for details.
On most systems the engine block temperature is monitored
at startup; other systems monitor the engine oil pressure,
coolant temperature, and time, as well. When the pre-set
conditions are met, the heater automatically engages.
Air Intake Heater
The air intake heater system will alert you when the engine
requires preheat. On the dash is a “WAIT TO START” warn-
ing light (See page 20
). This light alerts you to wait before
starting the engine.
Turn the key to IGN & ACC: the WAIT TO START light will
light up for bulb check.
Wait until the WAIT TO START light goes off before you start
the engine.
When the WAIT TO START light goes off, the preheat cycle is
complete and you can start the engine normally.
