Page 325 of 368

Habits
• Smooth, moderate operation can yield up to 10% savings in fuel.
• Steady speeds without stopping will usually give the best fuel
economy.
• Idling for long periods of time (greater than one minute) may waste
fuel.
• Anticipate stopping; slowing down may eliminate the need to stop.
• Sudden or hard accelerations may reduce fuel economy.
• Slow down gradually.
• Driving at reasonable speeds (traveling at 88 km/h [55 mph] uses 15%
less fuel than traveling at 105 km/h [65 mph]).
• Revving the engine before turning it off may reduce fuel economy.
• Using the air conditioner or defroster may reduce fuel economy.
• You may want to turn off the speed control in hilly terrain if
unnecessary shifting between third and fourth gear occurs.
Unnecessary shifting of this type could result in reduced fuel
economy.
• Warming up a vehicle on cold mornings is not required and may
reduce fuel economy.
• Resting your foot on the brake pedal while driving may reduce fuel
economy.
• Combine errands and minimize stop-and-go driving.
Maintenance
• Keep tires properly inflated and use only recommended size.
• Operating a vehicle with the wheels out of alignment will reduce fuel
economy.
• Use recommended engine oil. Refer to Lubricant specifications in
this chapter.
• Perform all regularly scheduled maintenance items. Follow the
recommended maintenance schedule and owner maintenance checks
found in your vehicle scheduled maintenance guide.
Conditions
• Heavily loading a vehicle or towing a trailer may reduce fuel economy
at any speed.
• Carrying unnecessary weight may reduce fuel economy (as much as
0.4 km/L [1 mpg] is lost for every 180 kg [400 lb] of weight carried).
2004 Navigator (nav)
Owners Guide (post-2002-fmt)
USA English (fus) Maintenance and Specifications
325
Page 348 of 368

SNOW TIRES AND CHAINS
Snow tires must be the same size and grade as the tires you
currently have on your vehicle.
The tires on your vehicle have all weather treads to provide traction in
rain and snow. However, in some climates, you may need to use snow
tires and chains.
Follow these guidelines when using snow tires and chains:
• Use only cable type chains or chains offered by Ford as an accessory
or equivalent. Other conventional link type chains may contact and
cause damage to the vehicle ’ s wheel house and/or body.
• Do not install chains on the front wheels. Chains on the front wheels
may interfere with suspension components.
• Chains are not recommended for use on the optional P275/65R18 tire.
• Install chains securely, verifying that the chains do not touch any
wiring, brake lines or fuel lines.
• Drive cautiously. If you hear the chains rub or bang against your
vehicle, stop and re-tighten the chains. If this does not work, remove
the chains to prevent damage to your vehicle.
• If possible, avoid fully loading your vehicle.
• Remove the tire chains when they are no longer needed. Do not use
tire chains on dry roads.
• The suspension insulation and bumpers will help prevent vehicle
damage. Do not remove these components from your vehicle when
using snow tires and chains.
• Do not exceed 48 km/h (30 mph) with tire chains on your vehicle.
MOTORCRAFT PART NUMBERS
Component 5.4L 4V V8 engine
Air filter element FA-1634
Battery (standard) BXT-65-650/BXT-65 – 750
Fuel filter FG-986B
Oil filter FL-820-S
PCV valve EV-248
2004 Navigator (nav)
Owners Guide (post-2002-fmt)
USA English (fus)Maintenance and Specifications
348
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
Page 354 of 368

MERCON and MERCON V type fluids are not interchangeable.
DO NOT mix MERCON and MERCON V. Use of a transmission
fluid that indicates dual usage (MERCON and MERCON V) in
an automatic transmission application requiring MERCON may
cause transmission damage. Use of any fluid other than the
recommended fluid may cause transmission damage. 2
Add 118 ml (4 oz.) of Additive Friction Modifier XL-3 or equivalent
meeting Ford specification EST-M2C118-A for complete refill of Ford
Limited Slip rear axles.
ENGINE DATA
Engine 5.4L 4V V8 engine
Cubic inches 330
Required fuel 91 octane
Firing order 1-3-7-2-6-5-4-8
Spark plug gap 1.3-1.4 mm (0.052-0.056 inch)
Ignition system Coil on plug
Compression ratio 9.5:1
VEHICLE DIMENSIONS
Vehicle dimensions 4x2 and 4x4 mm (in)
(1) Overall length 5232.0 (206)
(2) Vehicle width
(Body) 2000.0 (78.7)
(2) Vehicle width
with power running boards,
mirrors folded 2029 (79.9)
(2) Vehicle width
with fixed running boards 2088 (82.2)
(3) Overall height 1975.0 (77.8)
(4) Wheelbase 3018.0 (118.8)
(5) Track - Front 1701.0 (67.0)
(5) Track - Rear 1704.0 (67.1)
2004 Navigator (nav)
Owners Guide (post-2002-fmt)
USA English (fus)Maintenance and Specifications
354