Vehicles driven year-round in non-extreme climates should use a 50/50
mixture of engine coolant and distilled water for optimum cooling system
and engine protection.
What you should know about fail-safe cooling (4.6L V8 engine only)
If the engine coolant supply is depleted, this feature allows the vehicle to
be driven temporarily before incremental component damage is incurred.
The ªfail-safeº distance depends on ambient temperatures, vehicle load
and terrain.
Fail-safe cooling and engine oil temperature sensor (4.6L V8 only)
If the engine coolant and/or engine oil overheat, the vehicle limits engine
power before engine damage can occur. The instrument cluster can
provide up to four indicators to warn of coolant and/or oil overheat.
Warning lights/indicators Fail Safe cooling Oil Overheat Only*
(Engine oil pressure)OnOffÐwith normal
oil pressure
(Service engine soon)On Off
(Engine coolant temperature)On On
Engine coolant temperature gage Hot (H) area Hot (H) area
*Oil overheat warnings can be triggered in severe driving conditions, such as
towing heavy loads over mountainous terrain in extreme hot temperatures.
If the engine fluids reach even hotter temperatures, fail-safe cooling
protects the engine by limiting engine power further and may disable the
air conditioning system. The engine will automatically switch to
alternating cylinder operation. Each disabled cylinder acts as an air
pump and cools the engine. During this mode, the engine will run rough.
If continued operation increases the engine temperature to a critical
range, the engine will shut down. Steering and braking effort will
increase. Once engine temperature cools, the engine can be restarted.
When fail-safe mode is activated
You have limited engine power when in the fail-safe mode, so drive the vehicle
with caution. The vehicle will not be able to maintain high speed operation and
the engine will run rough. Remember that the engine is capable of completely
shutting down automatically to prevent engine damage, therefore:
1. Pull off the road as soon as safely possible and turn off the engine.
2. Arrange for the vehicle to be taken to an authorized dealer.
Maintenance and Specifications
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