What You Should Know About Fail-Safe
Cooling
If you deplete the engine coolant supply,
fail-safe cooling allows you to temporarily
drive your vehicle before you incur
incremental component damage. The
fail-safe distance depends on ambient
temperatures, vehicle load and terrain.
How Fail-Safe Cooling Works
If the engine begins to overheat, the engine
coolant temperature gauge will move to the
red (hot) area and:
the coolant temperature warning
light will illuminate
the service engine soon indicator
will illuminate.
If the engine reaches a preset
over-temperature condition, the engine
automatically switches to alternating cylinder
operation. Each disabled cylinder acts as an
air pump and cools the engine.
When this occurs, your vehicle will still
operate. However:
•
The engine power will be limited.
•
This will disable the air conditioning
system.
Continued operation increases the engine
temperature, causing the engine to
completely shut down. Your steering and
braking effort increases in this situation.
When the engine temperature cools, you can
re-start your engine. Take your vehicle to an
authorized dealer as soon as possible to
minimize engine damage.
When Fail-Safe Mode Is Activated
WARNINGS
Fail-safe mode is for use during
emergencies only. Operate your
vehicle in fail-safe mode only as long as
necessary to bring your vehicle to rest in a
safe location and seek immediate repairs.
When in fail-safe mode, your vehicle will have
limited power, will not be able to maintain
WARNINGS
high-speed operation, and may completely
shut down without warning, potentially losing
engine power, power steering assist, and
power brake assist, which may increase the
possibility of a crash resulting in serious
injury.
Never remove the coolant reservoir
cap while the engine is running or hot.
You have limited engine power when in the
fail-safe mode, so drive your vehicle with
caution. Your vehicle will not maintain
high-speed operation and the engine will
operate poorly.
Remember that the engine is capable of
automatically shutting down to prevent
engine damage. In this situation:
1. Pull off the road as soon as safely
possible and switch off the engine.
2. Tow your vehicle to an authorized dealer.
3. If this is not possible, wait a short period
for the engine to cool.
4. Check the coolant level and add if low.
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Navigator (TB5) Canada/United States of America, enUSA, First Printing
Maintenance
