What You Should Know About Fail-Safe Cooling - Ford 1998 F-150 Owner's Manual

Maintenance and care
Leave a 50/50 mixture of engine
coolant and water in your vehicle
year-round in non-extreme
climates.
What you should know about
fail-safe cooling (if equipped)
If the engine coolant supply is
depleted, this feature allows the
vehicle to be driven temporarily
before incremental component
damage is incurred. The "fail safe"
distance depends on ambient
temperatures, vehicle load and
terrain.
How fail-safe cooling works
If the engine overheats, the engine
H
will automatically switch from
eight to alternating four cylinder
operation. Each disabled cylinder
acts as an air pump and cools the
engine.
C
When this occurs, the engine
coolant temperature gauge will
move into the red area and the
light illuminates.
The service engine soon light will
illuminate, indicating that vehicle
service is required.
The vehicle will still operate, but
will have limited engine power and
no air conditioning capability.
Continued operation will increase
engine temperature and cause the
engine to completely shut down.
The vehicle will coast to a stop.
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