• Do not mix coolants. Add the coolant type originally equipped
in your vehicle. Refer to Maintenance product specifications and
capacities in this chapter.
Note: Do not use stop leak pellets or cooling system sealants/additives
as they can cause damage to the engine cooling and/or heating systems.
This damage would not be covered under your vehicle’s warranty.
• A large amount of water without engine coolant may be added, in case
of emergency, to reach a vehicle service location. In this instance, the
cooling system must be drained and refilled with a 50/50 mixture of
engine coolant and distilled water as soon as possible. Water alone
(without engine coolant) can cause engine damage from corrosion,
overheating or freezing.
• Do not use alcohol, methanol, brine or any engine coolants
mixed with alcohol or methanol antifreeze (coolant). Alcohol
and other liquids can cause engine damage from overheating or
freezing.
• Do not add extra inhibitors or additives to the coolant. These
can be harmful and compromise the corrosion protection of the engine
coolant.
For vehicles with overflow coolant systems with a non-pressurized cap
on the coolant recovery system, add coolant to the coolant recovery
reservoir when the engine is cool. Add the proper mixture of coolant and
water to the FULL COLD level. For all other vehicles which have a
coolant degas system with a pressurized cap, or if it is necessary to
remove the coolant pressure relief cap on the radiator of a vehicle with
an overflow system, follow these steps to add engine coolant.
WARNING: To reduce the risk of personal injury, make sure the
engine is cool before unscrewing the coolant pressure relief cap.
The cooling system is under pressure; steam and hot liquid can come
out forcefully when the cap is loosened slightly.
Add the proper mixture of coolant and water to the cooling system by
following these steps:
1. Before you begin, turn the engine off and let it cool.
2. When the engine is cool, wrap a thick cloth around the coolant
pressure relief cap on the coolant reservoir (a translucent plastic bottle).
Slowly turn cap counterclockwise (left) until pressure begins to release.
3. Step back while the pressure releases.
Maintenance and Specifications
347
2010 Navigator (nav)
Owners Guide (own2002), 1st Printing
USA (fus)