Mercury›Grand Marquis›1998›Overview/mercury/grand-marquis/1998/base/

1998 Mercury Grand Marquis

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

Body PASSENGER CARTransmission Automatic 4-spd

The 1998 Mercury Grand Marquis is a passenger car pairing an engine specified for 5.0 quarts of 5W-20 oil with a four-speed automatic transmission, returning EPA fuel-economy ratings of 15 mpg city, 22 mpg highway, and 18 mpg combined. The model year has drawn 180 owner complaints and seven recalls, with Engine & Engine Cooling dominating the report categories — a useful reference point against the broader 1990–2011 complaint arc, which crested at 487 reports in 2005 and bottomed out at 9 in 2011. Researchers can therefore read 1998 as a relatively early, low-complaint data point on the curve, offering a stable baseline against which the mid-decade spike and the subsequent taper can be benchmarked.

Model year2011 2010 2009 2008 2007 2006 2005 2004 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 torque85-105 ft-lbsOEM · verified

EPA fuel economy15/22/18 mpgEPA · 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 sizeP225-60R16OEM · verified

Wheel / rim7 inOEM · verified

Full specifications

Engine, drivetrain, dimensions and economy.

Engine & drivetrain NHTSA vPIC

Transmission

Automatic 4-spd

Dimensions & weight NHTSA vPIC

Overall length	212.2 in
Overall width	78 in
Overall height	56.7 in
Wheelbase	114.6 in
Curb weight	3796 lb
Track (front / rear)	63 / 65 in
Weight distribution (front / rear)	56/44

Ratings & economy EPA / vPIC

EPA city / highway / combined	15 / 22 / 18 mpg
Drivetrain	Rear-Wheel Drive
Passenger volume	109 cu ft
Cargo volume	21 cu ft
Recommended fuel	Regular Gasoline

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, DOT 3 brake fluid. Torque lug nuts to 85-105 ft-lbs, the oil drain plug to 19.0 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
Engine Coolant	ETHYLENE GLYCOL
Engine Oil	5W-20 · API
Engine Oil Capacity	5.0 qt

Engine torques

Crankshaft Pulley and/or Damper Bolts	114-121 ft-lbs
Intake Manifold to Engine Bolts	18.0 ft-lbs
Exhaust Manifold to Cylinder Head Bolts	18.0 ft-lbs
Engine Oil Pan Drain Plug	19.0 ft-lbs

Chassis torques

Lug Nuts	85-105 ft-lbs
Front Wheel Hub	221 ft-lbs

Ignition

Cylinder Firing Order	1-3-7-2-6-5-4-8
Curb Idle Speed (No Load)	800 rpm
Curb Idle Speed Variance (No Load)	25 rpm
Spark Plug Manufacturer	Motorcraft
Spark Plug Gap	0.052-0.056 in
Spark Plug Torque	11.0 ft-lbs
Ignition Timing	10, Not adjustable degrees
Ignition Timing Acceptable Variance	2 degrees

Battery & A/C

Refrigerant	R134a
Refrigerant Capacity	2.13 lbs
Oil Group	PAG
Oil Type	YN-12-D
Oil Capacity	7.00 oz
Standard BCI Group Number	65
Standard BCI Cranking Performance	650 cca
Optional BCI Group Number	65

Service checks

Pressure Test	13-18 psi
Radiator Cap Pressure Relief	13-18 psi
Thermostat Opening Temperature	192-199 °F
Key ON Engine OFF (KOEO)	30.0-45.0
Injector Primary Resistance	11-18 ohms

Brakes

Torque Caliper to Bracket	147 ft-lbs / 20 ft-lbs
Torque to Knuckle	85-105 ft-lbs / 50 ft-lbs
Minimum Pad Thickness	Front: 0.125; Rear: 0.125 in
Minimum Shoe Thickness	0.030
Rotor Max Parallel Variation	0.00035 in / 0.0004 in
Rotor Runout Limit	0.002 in
Rotor Nominal Thickness From	1.063 in / 0.56 in
Rotor Nominal Thickness To	1.063 in / 0.56 in

Multi-step torque procedures OEM · verified

Cylinder Head — tightening sequence 6 stages

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

1	30.0 ft. lbs.	30 ft. lbs
2	90 degrees	90 degrees
3	Loosen bolts 360 degrees	360 degrees
4	30.0 ft. lbs.	30 ft. lbs
5	90 degrees	90 degrees
6	90 degrees	90 degrees

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	Tire & Wheel Assembly (rotate)
Every 5,000 mi	Engine Oil (drain & refill) · Engine Oil Filter (replace)
Every 10,000 mi	Tire & Wheel Assembly (rotate)
Every 15,000 mi	Engine Coolant System (leak inspection) · Steering Linkage (inspect) · Suspension System (inspect)
Every 20,000 mi	Accessory Drive Belt (inspect)
Every 30,000 mi	Brake Linings (inspect) · Engine Air Filter Element (replace) · Engine Coolant System (drain, flush & refill) · Exhaust System Heat Shield (inspect) · Transmission Assembly (drain & refill)
At 50,000 mi	Engine Coolant System (drain, flush & refill)
Every 60,000 mi	PCV Valve (replace)
At 100,000 mi	Accessory Drive Belt (inspect)

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 Grand Marquis saw a sharp drop in consumer complaints to 180, well below the mid‑1990s peak of 383 in 1997 and far beneath the 395 complaints recorded in 2003, indicating a relative improvement in perceived reliability for that model year. Recall activity remained steady at seven recalls—matching the high level of 1995‑1997—while investigations fell to four, the lowest since 1990, suggesting fewer unresolved safety concerns. Technical Service Bulletins, however, surged to 170, the highest in the dataset, pointing to a growing number of manufacturer‑issued fixes despite the lower complaint count. The top complaint categories (engine cooling, exterior lighting, steering, suspension) and the modest figures for crash (9) and fire (8) complaints show no glaring systemic failures for 1998. Overall, 1998 sits near the bottom of the complaints trend while maintaining average recall exposure, making it a comparatively sound year to consider for a used purchase.

Open recalls

NHTSA campaigns

170

Service bulletins

Manufacturer communications

ODI investigations

Office of Defects Investigation

180

Owner complaints

9 involved a crash · 8 a fire

Owner complaints by model year NHTSA · this generation & adjacent

’90 ’91 ’92 ’93 ’94 ’95 ’96 ’97’98’99 ’00 ’01 ’02 ’03 ’04 ’05 ’06 ’07 ’08 ’09 ’10 ’11

Owner complaints filed with NHTSA, by component

All 180 complaints on record, top 8 components.

Engine & Engine Cooling23

Exterior Lighting16

Steering15

Suspension14

Electrical System13

Structure11

Power Train10

Tires9

Source: NHTSA Office of Defects Investigation complaint database.

Recalls NHTSA · verified

Showing 2 of 7 campaigns on record for this vehicle.

15E082000SteeringReported 06/10/2015

Dorman Products, Inc. (Dorman) is recalling certain model Dorman Steering Shafts, part number 425-359, Solutions Steering Shafts, part number 7-0359, and OE Solutions Steering Shafts, part number 425-359, manufactured… Remedy: Dorman will notify owners, and dealers will replace the steering shaft, free of charge. The recall began on October 28, 2015. Owners may contact Dorman customer service at…

08V051000Vehicle Speed Control:Cruise ControlReported 04/02/2008

FORD IS RECALLING 225,000 MY 1992-2003 ECONOLINE, MY 1993-1995 TAURUS SHO, MY 1992-1998 CROWN VICTORIA, MY 1993 BRONCO, F-SERIES, MY 1995-1997 F-SERIES SUPER DUTY STRIPPED CHASSIS, MY 1992-1998 MERCURY GRAND MARQUIS… Remedy: DEALERS WILL INSTALL A NEW WIRING HARNESS, OR REPLACE THE MATING ELECTRICAL COMPONENT. THE RECALL BEGAN ON FEBRUARY 18, 2008. OWNERS MAY CONTACT FORD AT 1-800-392-3673.

Technical service bulletins NHTSA · verified

Showing 5 of 170 bulletins on record with NHTSA.

Bulletin	Date	Component	Summary
CSP 08B04	2008-05-15	Fuel System, Gasoline	FORD/LINCOLN MERCURY: CERTAIN 1992-2001 MODEL YEAR CROWN VICTORIA, GRAND MARQUIS, AND…
07212	2007-10-01	Engine And Engine Cooling	SOME 1997-2008 VEHICLES EQUIPPED WITH A 4.6L 2V, 5.4L 2V, OR 6.8L 2V ENGINE--SPARK PLUG…
05N04	2005-12-14	Engine And Engine Cooling	EXTENDED COVERAGE PROGRAM 05N04 - EXTENDED COVERAGE FOR COMPOSITE INTAKE MANIFOLD. THIS…
041601	2005-11-14	Engine And Engine Cooling	WDS COP KIT DIAGNOSTIC TIP - COIL ON PLUG (COP) IGNITION SYSTEMS - ENGINE MISFIRE OR…
042107	2004-12-13	Power Train	GENERAL (PCM) POWER TRAIN CONTROL MODULE PROGRAMMING PROCEDURES. *TT

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 Grand Marquis. 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 Grand Marquis take?

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

Does the 1998 Grand Marquis have open recalls?

NHTSA lists 7 recall campaign(s) for this model year. Check your specific vehicle by VIN.

What gas mileage does the Grand Marquis get?

EPA figures are 15 city / 22 highway / 18 combined mpg.