Page 317 of 368

Coolant refill capacity
To find out how much fluid your vehicle ’ s cooling system can hold, refer
to Refill capacities in this chapter.
Fill your engine coolant reservoir as outlined in Adding engine coolant
in this chapter.
Severe climates
If you drive in extremely cold climates (less than – 36 ° C[ – 34 ° F]):
• It may be necessary to increase the coolant concentration
above 50%.
• NEVER increase the coolant concentration above 60%.
• Increased engine coolant concentrations above 60% will
decrease the overheat protection characteristics of the engine
coolant and may cause engine damage.
• Refer to the chart on the coolant container to ensure the
coolant concentration in your vehicle will provide adequate
freeze protection at the temperatures in which you drive in the
winter months.
If you drive in extremely hot climates:
• It is still necessary to maintain the coolant concentration
above 40%.
• NEVER decrease the coolant concentration below 40%.
• Decreased engine coolant concentrations below 40% will
decrease the corrosion protection characteristics of the engine
coolant and may cause engine damage.
• Decreased engine coolant concentrations below 40% will
decrease the freeze protection characteristics of the engine
coolant and may cause engine damage.
• Refer to the chart on the coolant container to ensure the
coolant concentration in your vehicle will provide adequate
protection at the temperatures in which you drive.
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
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.
2004 Navigator (nav)
Owners Guide (post-2002-fmt)
USA English (fus) Maintenance and Specifications
317
Page 349 of 368

Component 5.4L 4V V8 engine
Spark plugs* AGSF-32PM
* Refer to Vehicle Emissions Control Information (VECI) decal for spark
plug gap information.
REFILL CAPACITIES
Fluid Ford Part
Name Application Capacity
Brake fluid Motorcraft High
Performance
DOT 3 Motor
Vehicle Brake
Fluid All Fill to line on
reservoir
Engine oil
(includes filter
change) 6
Motorcraft SAE
5W-20 Premium
Synthetic Blend
Motor Oil (US)
Motorcraft SAE
5W-20 Super
Premium Motor
Oil (Canada) All 6.6L (7.0
quarts)
Fuel tank N/A All 106 L (28
gallons)
Power steering
fluid Motorcraft
MERCON AT F All Fill to line on
reservoir
Transmission
fluid 1
Motorcraft
MERCON AT F 4 x 2 vehicles 15.0L (15.9
quarts) 2
4 x 4 vehicles 15.5L (16.4
quarts) 2
Transfer case
fluid Motorcraft
MERCON AT F 4 x 4 vehicles 1.9L (2.0
quarts)
Engine coolant 3
Motorcraft
Premium Gold
Engine Coolant
(yellow-colored) without aux rear
heat 21.0L (22.2
quarts)
with aux rear
heat 23.0L (24.3
quarts)
2004 Navigator (nav)
Owners Guide (post-2002-fmt)
USA English (fus) Maintenance and Specifications
349
Page 351 of 368

an automatic transmission application requiring MERCON may
cause transmission damage. Use of any fluid other than the
recommended fluid may cause transmission damage. 2
Indicates only approximate dry-fill capacity. Some applications may vary
based on cooler size and if equipped with an in-tank cooler. The amount
of transmission fluid and fluid level should be set by the indication on
the dipstick ’ s normal operating range.3
Add the coolant type originally equipped in your vehicle. 4
Your vehicle ’ s rear axle is filled with a synthetic rear axle lubricant and
is considered lubricated for life. These lubricants are not to be checked
or changed unless a leak is suspected, service is required or the axle has
been submerged in water. The axle lubricant should be changed any time
the axle has been submerged in water.
Service refill capacities are determined by filling the rear axle 23mm (0.9
inch) below the bottom of the filler hole. 5
Add 118 ml (4 oz.) of Additive Friction Modifier XL-3 or equivalent
meeting Ford specification EST-M2C118 – A for complete refill of Limited
Slip axles. For complete refills, fill using the Additive Friction Modifier
first. 6
Use of synthetic or synthetic blend motor oil is not mandatory. Engine
oil need only meet the requirements of Ford specification
WSS-M2C153 – H and the API Certification mark.
LUBRICANT SPECIFICATIONS
Item Ford part
name Ford part
number Ford
specification
Hinges, latches,
striker plates
and rotors, seat
tracks, fuel filler
door hinge and
spring Multi-Purpose
Grease XG-4 or XL-5 ESR-M1C159-A
or ESB-M1C93-B
Lock cylinders Penetrating and
Lock Lubricant Motorcraft XL-1 ESB-M2C75-B
2004 Navigator (nav)
Owners Guide (post-2002-fmt)
USA English (fus) Maintenance and Specifications
351