How Fail-Safe Cooling Works; When Fail-Safe Mode Is Activated - Mercury mariner 2009 Owner's Manual

Maintenance and Specifications

How fail-safe cooling works

If the engine begins to overheat:
• The engine coolant temperature gauge will move to the red (hot)
area.
• The service engine soon
If the engine reaches a preset over-temperature condition, the engine
will automatically switch to alternating cylinder operation. Each disabled
cylinder acts as an air pump and cools the engine.
When this occurs the vehicle will still operate. However:
• The engine power will be limited.
• The air conditioning system will be disabled.
Continued operation will increase the engine temperature and the engine
will completely shut down, causing steering and braking effort to
increase.
Once the engine temperature cools, the engine can be re-started. Take
your vehicle to an authorized dealer as soon as possible to minimize
engine damage.

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.
3. If this is not possible, wait a short period for the engine to cool.
4. Check the coolant level and replenish if low.
WARNING: Never remove the coolant reservoir cap while the
engine is running or hot.
5. Re-start the engine and take your vehicle to an authorized dealer.
Driving the vehicle without repairing the engine problem
increases the chance of engine damage. Take your vehicle to an
authorized dealer as soon as possible.
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2009 Mariner (mrn)
Owners Guide, 1st Printing
USA (fus)
indicator light will illuminate.