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1998 Mercury Mountaineer

Factory specifications, fluid capacities, torque values, EPA fuel economy and the federal safety record for the 1998 Mountaineer.

Body SUV

The 1998 Mercury Mountaineer is an SUV maintained with 5.0 quarts of 5W-20 API engine oil, though its ownership record includes 262 total complaints and 6 recalls with tires identified as the top complaint area. This specific year falls within a model history spanning 1996 to 2010 that saw complaint counts range from a low of 3 to a high of 390. Consequently, the 1998 Mountaineer occupies a middle ground in the model's reliability history, exhibiting significantly more reported issues than the 1996 model year but fewer than the peak problem year of 2002.

Model year2010 2009 2008 2007 2006 2005 2004 2003 1998

Quick specs

Fluid capacities, tune-up values and fuel economy at a glance.

Engine oil capacity5.0 qtOEM · verified

Engine oil type5W-20 APIOEM · verified

Lug nut torque100 ft-lbsOEM · verified

Fitment & sizes

Replacement part sizes and factory part numbers — battery, bulbs, filters and belts.

From the factory this vehicle uses a BCI 65 · 650 CCA battery. Each part links to every other vehicle that shares it, so a part you already stock may fit more of your fleet than you'd expect.

Battery groupBCI 65 · 650 CCAOEM · verified

Tire sizeP225-70R15OEM · verified

Wheel / rim7-J inOEM · verified

Service quick specs OEM factory data

Capacities, torques and tune-up values from the factory service manual.

This engine holds 5.0 qt of 5W-20 API engine oil, SYNTHETIC · 75W-140 · GL-5 in the differential, DOT 3 brake fluid. Torque lug nuts to 100 ft-lbs, the oil drain plug to 17.0-22.0 ft-lbs. The firing order is 1-3-7-2-6-5-4-8. Note the cylinder-head bolts finish on a torque angle (torque-to-yield) — they stretch permanently and should be replaced, not reused, during any head service.

Lubricants & capacities

Brake Fluid	DOT 3
Differential Gear Oil	SYNTHETIC · 75W-140 · GL-5
Differential Gear Oil Capacity	5.5 Pints (rear)
Engine Oil	5W-20 · API
Engine Oil Capacity	5.0 qt
Engine Oil	5W-30 · API
Engine Oil Capacity	5.0 qt
Power Steering Fluid	ATF

Engine torques

Camshaft Bearing/Carrier Cap Bolts or Studs	11-12 ft-lbs
Crankshaft Pulley and/or Damper Bolts	110-130 (302) ft-lbs
Intake Manifold to Engine Bolts	7.4 ft-lbs
Exhaust Manifold to Cylinder Head Bolts	16.0 ft-lbs
Intake Manifold to Engine Bolts	Lower: 23.0-; Upper: 12.0-
Exhaust Manifold to Cylinder Head Bolts	26.0-32.0 ft-lbs
Main Bearings	67-74 ft-lbs
Engine Oil Pan Drain Plug	17.0-22.0 ft-lbs

Chassis torques

Lug Nuts	100 ft-lbs
Transfer Case Fill Plug	4WD: 18.0, With AWD: 13.0 ft-lbs
Transfer Case Drain Plug	4WD: 18.0, With AWD: 13.0 ft-lbs
Front Wheel Hub	184 ft-lbs

Ignition

Cylinder Firing Order	1-4-2-5-3-6
Cylinder Firing Order	1-3-7-2-6-5-4-8
Curb Idle Speed (No Load)	750 SOHC rpm
Curb Idle Speed Variance (No Load)	25 rpm
Curb Idle Speed (No Load)	750 rpm
Curb Idle Speed Variance (No Load)	25 rpm
Spark Plug Manufacturer	Motorcraft
Spark Plug Gap	0.052-0.056 in

Battery & A/C

Refrigerant	R134a
Refrigerant Capacity	1.88 lbs
Oil Group	PAG
Oil Type	68
Oil Capacity	9.00 oz
Standard BCI Group Number	65
Standard BCI Cranking Performance	650 cca
Standard BCI Group Number	65

Service checks

Pressure Test	13-18 psi
Radiator Cap Pressure Relief	13-18 psi
Thermostat Opening Temperature	183-190 °F
Key ON Engine OFF (KOEO)	30-45
Engine Oil Pressure	40-60 psi
Engine Oil Pressure RPM	2000 rpm
Intake Valve Lash	Hydraulic in
Exhaust Valve Lash	Hydraulic in

Brakes

Brake Application	WITH REAR DISC / WITH STANDARD
Torque Caliper to Bracket	20 ft-lbs / 21-26 ft-lbs
Torque to Knuckle	80 ft-lbs / 73-97 ft-lbs
Minimum Pad Thickness	Front: 0.030; Rear: 0.030 specification
Brake Application	WITH REAR DISC / WITH STANDARD
Rotor Max Parallel Variation	0.0002 in
Rotor Runout Limit	0.005 in
Rotor Discard at or Under	0.433 in / 0.965 in

Multi-step torque procedures OEM · verified

Connecting Rod (Large End) Bearings — tightening sequence 1 stages

15 ft. lbs., Step 2: 90

15 ft. lbs

Cylinder Head — tightening sequence 3 stages

Prep Do not reuse old bolts. Coat bolt threads with clean engine oil.

1	26.0 ft. lbs.	26 ft. lbs
2	90 degrees	90 degrees
3	90 degrees	90 degrees

Cylinder Head — tightening sequence 3 stages

Prep Do not reuse old bolts. Coat bolt threads with clean engine oil.

1	25.0-35.0 ft. lbs.	25–35 ft. lbs
2	45.0-55.0 ft. lbs.	45–55 ft. lbs
3	85 degrees-95 degrees	85 degrees

Engine Flywheel Bolts — tightening sequence 1 stages

19-25 ft. lbs., Step 2: 90

19–25 ft. lbs

Factory maintenance schedule OEM · verified

Normal service, condensed from the factory interval matrix.

Under the factory schedule, replace the engine oil and filter every 5,000 mi; coolant every 30,000 mi. The big-interval services (every 30,000 mi for coolant, and the transmission fluid) are the ones owners most often skip — on a lower-mileage example, assume the original fluids are still in it and check them first.

At 5,000 mi	Driveshaft Slip Yoke (lubricate) · Driveshaft U-Joint (lubricate) · Exhaust System (Complete) (inspect) · Shift Linkage (lubricate) · Steering Linkage (lubricate) · Suspension System (lubricate)
Every 5,000 mi	Engine Oil (drain & refill) · Engine Oil Filter (replace)
Every 10,000 mi	Driveshaft Slip Yoke (lubricate) · Driveshaft U-Joint (lubricate) · Exhaust System (Complete) (inspect) · Shift Linkage (lubricate) · Steering Linkage (lubricate) · Suspension System (lubricate)
Every 12,000 mi	Battery (inspect)
Every 15,000 mi	Brake System (inspect) · Disc Brake Caliper Guide Pin (lubricate) · Engine Coolant System (leak inspection)
Every 30,000 mi	Accessory Drive Belt (inspect) · Engine Air Filter Element (replace) · Engine Coolant System (drain, flush & refill) · Fuel Filter (replace) · Throttle Body Lever Stud (lubricate) · Transmission Assembly (drain & refill)
At 45,000 mi	Engine Coolant System (drain, flush & refill)
At 60,000 mi	Accessory Drive Belt (inspect)
Every 60,000 mi	PCV Valve (replace)

Reliability & federal safety record

Owner-reported issues, recalls, investigations and service bulletins on record with NHTSA — an unfiltered look at what owners actually experience.

The 1998 Mercury Mountaineer sits at a critical juncture in its generation, following the sharp spike in complaints (369) and recalls (7) in 1997, yet still registering elevated figures—262 complaints and 6 recalls—relative to later years. This year also marks the peak of federal investigations (7), suggesting systemic issues were under heightened scrutiny, though the data doesn’t specify root causes. Complaint trends reveal a focus on tires (102 reports) and vehicle speed control (33), alongside notable fire-related complaints (24), which align with broader concerns during this era. Compared to 1999’s decline in complaints (166) and subsequent stabilization, 1998 appears to be a transitional year where early-generation flaws were being addressed but not yet fully resolved. The high volume of TSBs (288) indicates manufacturer awareness of recurring problems, but the persistence of safety-related complaints tempers confidence. **Takeaway: While not the worst year, 1998 is a riskier choice—opt for a 1999 or later model if reliability is the priority.**

Open recalls

NHTSA campaigns

288

Service bulletins

Manufacturer communications

ODI investigations

Office of Defects Investigation

262

Owner complaints

22 involved a crash · 24 a fire

Owner complaints by model year NHTSA · this generation & adjacent

’96 ’97’98’99 ’00 ’01 ’02 ’03 ’04 ’05 ’06 ’07 ’08 ’09 ’10

Owner complaints filed with NHTSA, by component

All 262 complaints on record, top 8 components.

Tires102

Vehicle Speed Control33

Electrical System16

Engine & Engine Cooling14

Seats12

Latches/Locks/Linkages9

Suspension8

Power Train7

Source: NHTSA Office of Defects Investigation complaint database.

Recalls NHTSA · verified

Showing 2 of 6 campaigns on record for this vehicle.

00T005000Tires:Tread/BeltReported 21/08/2000

TIRE DESCRIPTION: FIRESTONE WILDERNESS AT, SIZE P235/75R15, PRODUCED AT THE DECATUR, ILLINOIS TIRE PLANT AND ALL FIRESTONE RADIAL ATX AND RADIAL ATX II TIRES, SIZE P235/75R15. OPERATION OF THESE TIRES AT LOW INFLATION… Remedy: THE REPLACEMENT/REIMBURSEMENT PROGRAM FOR THIS CAMPAIGN EXPIRED ON AUGUST 29, 2001. HOWEVER, CUSTOMERS SHOULD CONTACT FIRESTONE CUSTOMER SERVICE AT 1-800-465-1904 FOR POSSIBLE…

00V422000Vehicle Speed ControlReported 27/12/2000

VEHICLE DESCRIPTION: SPORT UTILITY VEHICLES EQUIPPED WITH 4.0L SOHC ENGINES AND STILL RETAIN THE ORIGINAL THROTTLE BODY (PART NUMBERS 97JF-9E926AB OR 97JF-9E926-AC). SOME OF THE ORIGINAL THROTTLE BODIES INSTALLED… Remedy: DEALERS WILL REPLACE THE ORIGINAL THROTTLE BODIES.

Technical service bulletins NHTSA · verified

Showing 5 of 288 bulletins on record with NHTSA.

Bulletin	Date	Component	Summary
030508	2005-04-01	Power Train	FRONT AXLE LEAKS FLUID FROM VENT TUBE - VEHICLES EQUIPPED WITH 4X4 OR AWD. *TT
042107	2004-12-13	Power Train	GENERAL (PCM) POWER TRAIN CONTROL MODULE PROGRAMMING PROCEDURES. *TT
04217	2004-11-01	Power Train	GENERAL POWER TRAIN CONTROL MODULE (PCM) PROGRAMMING PROCEDURES. *TT
0475	2004-01-01	Electrical System	DRIVEABILITY-MALFUNCTION INDICATOR LAMP (MIL) ILLUMINATED-DIAGNOSTIC TROUBLE CODES…
02138	2003-11-10	Power Train	LOW LINE PRESSURE READING AT WIDE OPEN THROTTLE (WOT), SLIPPING SHIFTS AND / OR DELAYED…

Common OBD-II trouble codes

The most common OBD-II codes for this vehicle's emissions system. These are standardized SAE J2012 definitions, not vehicle-specific fault reports.

P0420

Catalyst system efficiency below threshold — Bank 1

P0300

Random / multiple cylinder misfire detected

P0171

System too lean — Bank 1

P0455

Evaporative emission system leak detected — large leak

P0128

Coolant thermostat below regulating temperature

P0442

Evaporative emission system leak detected — small leak

VIN tools

Decode factory build data for a specific vehicle by VIN.

VIN

Decode a VIN to confirm the transmission and build data for a specific Mountaineer. OEM

Build data

Plant, GVWR class, engine and body data for any 17-character VIN.

Recalls

Check open recall campaigns against a specific vehicle by VIN.

Vehicles with shared specs

Find every vehicle that shares this one's battery, bulbs, oil capacity, platform or parts.

Group 65 battery Vehicles taking 5.0 qt

Reference guides

Cross-vehicle references for the kinds of data on this page.

Vehicle recalls & TSBs OBD-II trouble codes Torque specifications Maintenance schedules Fluid capacities & specs

Frequently asked

How much oil does the 1998 Mountaineer take?

5.0 qt of 5W-20 API, per the factory manual.

Does the 1998 Mountaineer have open recalls?

NHTSA lists 6 recall campaign(s) for this model year. Check your specific vehicle by VIN.