MileageCurve What breaks, and at what mileage

Lincoln Navigator 1998–2002

1st generation · UN173 (Ford U platform) · 696 complaints, 309 with mileage

Owners filed 696 complaints with NHTSA about the 1998–2002 Lincoln Navigator, and 309 of them record the mileage at which the failure happened. That is enough to show not just what fails, but when.

Failures are spread across the mileage range, with the middle half between 56,641 and 121,000 miles. The median is 85,500 miles.

The most-reported areas are the tyres (21.8% of complaints, typically around 50,000 miles), the electrical system (9.9% of complaints, typically around 94,000 miles), the suspension (8.2% of complaints, typically around 72,840 miles).

When failures happen

0–5k: 11 complaints (3.6%)0–5k5–10k: 1 complaints (0.3%)10–20k: 6 complaints (1.9%)10–20k20–30k: 9 complaints (2.9%)30–40k: 13 complaints (4.2%)30–40k40–50k: 25 complaints (8.1%)50–60k: 17 complaints (5.5%)50–60k60–70k: 32 complaints (10.4%)70–80k: 22 complaints (7.1%)70–80k80–90k: 29 complaints (9.4%)90–100k: 22 complaints (7.1%)90–100k100–120k: 40 complaints (12.9%)120–140k: 26 complaints (8.4%)120–140k140–160k: 21 complaints (6.8%)160–200k: 22 complaints (7.1%)160–200k200k+: 13 complaints (4.2%)400

10% of failures occur by 34,219 miles · a quarter by 56,641 · median 85,500 · three quarters by 121,000 · 90% by 163,000. Based on 309 complaints that record mileage.

What fails, and when

SystemComplaintsShareTypical mileageMiddle half
Tires15221.8%50,00038,000–78,000
Electrical System699.9%94,00072,500–133,000
Suspension578.2%72,84052,000–124,233
Engine And Engine Cooling578.2%101,00081,025–134,000
Vehicle Speed Control557.9%93,75170,000–117,000
Power Train446.3%76,00066,000–100,000
Steering415.9%69,00052,800–92,000
Wheels284.0%
Air Bags284.0%89,74634,219–160,000
Visibility273.9%

By model year

YearComplaintsWith mileage
199824081
199915566
200013754
200111674
20024834

Which systems, and when

Complaints about this generation are not spread evenly across the vehicle, and the systems that generate the most of them do not all fail at the same point in a car's life. The median failure across all systems here is 85,500 miles; the figures below show which parts of the car run ahead of that and which run behind.

The tyres account for 21.8% of complaints (152 reports, 37 of them with a mileage figure), and they fail early — a median of 50,000 miles, well before the vehicle's overall median. Failures clustered this far below the rest of the car usually point to a design or manufacturing problem rather than wear, because wear does not selectively target one system on low-mileage examples. The middle half of these reports falls between 38,000 and 78,000 miles.

The electrical system accounts for 9.9% of complaints (69 reports, 44 of them with a mileage figure), with a median of 94,000 miles, close to the vehicle's overall pattern. The middle half of these reports falls between 72,500 and 133,000 miles.

The suspension accounts for 8.2% of complaints (57 reports, 24 of them with a mileage figure), with a median of 72,840 miles, close to the vehicle's overall pattern. The middle half of these reports falls between 52,000 and 124,233 miles.

The engine and its cooling system accounts for 8.2% of complaints (57 reports, 37 of them with a mileage figure), with a median of 101,000 miles, close to the vehicle's overall pattern. The middle half of these reports falls between 81,025 and 134,000 miles.

Throttle and speed control accounts for 7.9% of complaints (55 reports, 32 of them with a mileage figure), with a median of 93,751 miles, close to the vehicle's overall pattern. The middle half of these reports falls between 70,000 and 117,000 miles.

The transmission and driveline accounts for 6.3% of complaints (44 reports, 21 of them with a mileage figure), with a median of 76,000 miles, close to the vehicle's overall pattern. The middle half of these reports falls between 66,000 and 100,000 miles.

Differences between model years

Within this generation, complaint volume is not constant across model years. The 1998 model year drew the most — 240 complaints — while 2002 drew the fewest at 48. The median year sits at 137.

The first year of the generation, 1998, sits above the median. That is a common pattern — early production of a redesigned vehicle tends to surface problems that later years do not repeat — and it is worth weighing when choosing between years.

Recalls and what they cover

No recall campaigns covering this generation appear in NHTSA's post-2010 recall file. That is not the same as an absence of problems — recalls address safety defects specifically, and many of the complaints above concern faults that are expensive or annoying without meeting that threshold.

Reported severity

Of the 696 complaints filed against this generation, 59 reported a crash; 77 reported a fire; 85 reported an injury; 17 reported a fatality. Crash-involved reports represent 8.5% of the total.

These are owner-reported outcomes, not verified investigations, and they are not adjusted for how many of these vehicles are on the road. They are included because the distinction between a fault that strands a car and a fault that causes a collision is the one that matters most, and it is not visible in a complaint count alone.

What this means if you are buying one

For a buyer, failures on this generation are spread rather than concentrated: the middle half falls between 56,641 and 121,000 miles, with a median of 85,500. There is no single mileage threshold to watch, which means condition and maintenance records are more informative than the odometer.

On inspection, the tyres and the electrical system are where this generation's reports concentrate, so those are the areas worth a specific look. The tyres in particular shows a median failure mileage of 50,000, which gives a concrete number to compare against the odometer of any car you are considering.

None of this is a substitute for a pre-purchase inspection on the individual car. Aggregate patterns describe a population; the example in front of you has its own history.

Documented problems

Air suspension 1998-2002

Rear (and on 4x4 models, front) air springs leak and the compressor burns out from over-cycling; symptoms are a sagging or squatting rear end, ride-height faults and nose-dive under braking. Height sensors and control module electrical faults are secondary causes.

Cylinder head spark plug threads (5.4L 2-valve) 1998-2002 (5.4L 2-valve)

The 2-valve Triton aluminum heads have too few spark plug thread engagements; plugs (commonly #2/#3/#4) work loose and eject from the head under compression, typically at 60,000-100,000 miles, stripping the threads. Ford revised the head design for 2003.

What owners reported

1998 · 10,000 miles · Vehicle Speed Control
TL*THE CONTACT OWNS A 1998 LINCOLN NAVIGATOR. THE VEHICLE SPEED CONTROL WAS DEACTIVATED FOR THE FORD RECALL. THE CONTACT STATED THAT THE DEALER DEACTIVATED THE SPEEDOMETER WHEN THE CRUISE CONTROL WAS DEACTIVATED. WHILE DRIVING APPROXIMATELY 65 MPH, THE CONTACT'S VEHICLE WAS REAR ENDED BY ANOTHER VEHICLE AND DESTROYED. TWO OCCUPANTS WERE INJURED AND A POLICE REPORT WAS FILED. THE RECALL NUMBER…
1998 · 10,000 miles · Air Bags
TL*THE CONTACT OWNS A 1998 LINCOLN NAVIGATOR. THE VEHICLE SPEED CONTROL WAS DEACTIVATED FOR THE FORD RECALL. THE CONTACT STATED THAT THE DEALER DEACTIVATED THE SPEEDOMETER WHEN THE CRUISE CONTROL WAS DEACTIVATED. WHILE DRIVING APPROXIMATELY 65 MPH, THE CONTACT'S VEHICLE WAS REAR ENDED BY ANOTHER VEHICLE AND DESTROYED. TWO OCCUPANTS WERE INJURED AND A POLICE REPORT WAS FILED. THE RECALL NUMBER…
1998 · 38,216 miles · Steering
WHILE DRIVING, THE LEFT TIE ROD SEPARATED, WHICH ALMOST CAUSED AN ACCIDENT. *JB WHILE DRIVING, THE RIGHT TIE ROD SEPARATED. (ALL PARTS WERE REPLACED BY THE DEALER) THE CONSUMER WAS ABLE TO STOP THE VEHICLE WITHOUT CAUSING AN ACCIDENT BECAUSE BOTH FAILURES OCCURRED AT A LOW SPEED. WHEN THE TIE ROD BROKE, ALONG WITH THE INNER BINDING, THE REACTION WAS EXTREMELY VIOLENT AND DIFFICULT TO CONTROL…
1998 · 38,216 miles · Suspension
WHILE DRIVING, THE LEFT TIE ROD SEPARATED, WHICH ALMOST CAUSED AN ACCIDENT. *JB WHILE DRIVING, THE RIGHT TIE ROD SEPARATED. (ALL PARTS WERE REPLACED BY THE DEALER) THE CONSUMER WAS ABLE TO STOP THE VEHICLE WITHOUT CAUSING AN ACCIDENT BECAUSE BOTH FAILURES OCCURRED AT A LOW SPEED. WHEN THE TIE ROD BROKE, ALONG WITH THE INNER BINDING, THE REACTION WAS EXTREMELY VIOLENT AND DIFFICULT TO CONTROL…

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