JeepWrangler1991Overview/jeep/wrangler/1991/base/

1991 Jeep Wrangler

Factory specifications, fluid capacities, torque values, EPA fuel economy and the federal safety record for the 1991 Wrangler.

The 1991 Jeep Wrangler falls within the model's complaint history spanning 1990 through 2023, powered by an engine requiring 4 quarts of oil with filter at API-grade viscosities of 20W-40, 20W-50, or 10W-40. The model year accumulated 94 total owner complaints — with fuel system, gasoline issues ranking as the top complaint area — alongside 8 recalls, placing it in a comparatively quiet zone of the Wrangler's reliability record that ranges from a low of just 5 complaints in 1996 to a high of 1,793 in 2018. That relatively modest complaint volume suggests the 1991 Wrangler represents an early, lower-risk chapter in the model's history, though its recall count and fuel system concerns mean it is not without documented vulnerabilities for researchers to weigh.

Model year202620252024202320222021202019941991

Quick specs

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

Engine oil capacity4 qt w/ filterOEM · verified
Engine oil type20W-40 / 20W-50 / 10W-40 APIOEM · verified

Performance & power Independent road tests

0–60 mph, quarter-mile, horsepower and torque from independent road tests.

Independent road tests for the Wrangler of this era, listed by trim and engine — this page spans more than one engine, so no single horsepower figure is shown.

15.4 sec0–60 mph (tested)quickest 15.40 sec — 1990 Sahara 2-door
YearTrim / engine0–60¼ mileHPDrivetrain
1990Sahara 2-door 4.2L I-615.40 sec20.00 sec112 hp4x4

Service quick specs OEM factory data

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

This engine holds 4 qt w/ filter of 20W-40 / 20W-50 / 10W-40 API engine oil, 75W-90 · GL-5 · 80W-140 in the differential.

Lubricants & capacities

Differential Gear Oil75W-90 · GL-5 · 80W-140
Differential Gear Oil Capacity2.5 Pints
Engine CoolantHOAT · MS9769
Engine Oil20W-40 · 20W-50 · API · 10W-40 · 5W-30
Engine Oil Capacity4 qt w/ filter
Engine Oil20W-40 · 20W-50 · API · 10W-40 · 5W-30
Engine Oil Capacity6 qt w/ filter
Power Steering FluidMS-5931

Factory maintenance schedule OEM · verified

Normal service, condensed from the factory interval matrix.

Under the factory schedule, replace the engine oil and filter every 7,500 mi; spark plugs every 60,000 mi; coolant every 7,500 mi. The big-interval services (every 7,500 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.

Every 7,500 miCV Joint Boot (inspect) · Differential (inspect fluid level) · Driveshaft U-Joint (lubricate) · Engine Coolant System (leak inspection) · Engine Oil (drain & refill) · Engine Oil Filter (replace)
Every 30,000 miBands (adjust) · Body Latches, Locks & Hinges (inspect) · Brake System (inspect) · Drive Axle Assembly (drain & refill) · Engine Air Filter Element (replace) · Engine Breather Filter (clean)
At 52,500 miEngine Coolant System (drain, flush & refill)
Every 60,000 miAccessory Drive Belt (inspect) · Battery (replace) · Distributor Cap (inspect) · Distributor Rotor (inspect) · Spark Plug Wires (replace) · Vacuum Line (inspect)
Every 82,500 miOxygen Sensor (replace)

Owner how-tos

Condensed service procedures for routine maintenance. Procedures that require dealer diagnostic equipment are identified and summarized only.

Common procedures

Key fob — remote (RKE) programming programming new fob buttons Dealer tool OEM · verified
Tool requiredDRBIII scan tool (dealer / locksmith)
WhyTransmitter codes are written into the receiver in the passenger door module
Anti-theft (SKIS) — module initialization after immobilizer module replacement Dealer tool OEM · verified
When neededAfter Sentry Key Immobilizer Module (SKIM) replacement
Tool requiredDRBIII scan tool
Also requiredThe vehicle's four-digit PIN code

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 1991 Jeep Wrangler logged 94 federal complaints, primarily concentrated in the Fuel System, Gasoline (16), Engine & Engine Cooling (13), Seat Belts (11), and Parking Brake (11), alongside 4 crash and 3 fire complaints. Compared to the adjacent 1990 (91 complaints, 7 recalls) and 1992 (92 complaints, 6 recalls) model years, the 1991 Wrangler maintains a nearly identical, low-complaint baseline. Across the broader 1990-1995 generation arc, federal complaints steadily escalate from 91 in 1990 to 221 by 1995, while recalls inversely decline from a high of 8 in 1991 down to 3 in 1995. The 1991 model sits firmly at the bottom of this rising complaint arc, sharing the lowest complaint volume of the decade with 1990 and 1992 while simultaneously bearing the generation's highest recall count; the data doesn't specify root causes, but this high recall-to-complaint ratio suggests the manufacturer proactively addressed safety defects before they resulted in widespread owner dissatisfaction. Consequently, the 1991 Wrangler is an excellent used buy within its era, offering the lowest documented complaint rate alongside maximum recall saturation, meaning the most significant factory issues were likely remedied decades ago.

8
Open recalls
NHTSA campaigns
10
Service bulletins
Manufacturer communications
4
ODI investigations
Office of Defects Investigation
94
Owner complaints
4 involved a crash · 3 a fire

Owner complaints filed with NHTSA, by component

All 94 complaints on record, top 8 components.

Fuel System, Gasoline16
Engine & Engine Cooling13
Seat Belts11
Parking Brake11
Power Train10
Electrical System8
Service Brakes, Hydraulic6
Tires2

Source: NHTSA Office of Defects Investigation complaint database.

Recalls NHTSA · verified

Showing 2 of 8 campaigns on record for this vehicle.

06E026000Exterior LightingReported 23/03/2006

CERTAIN PRO-A MOTORS CORNER LAMPS, TURN SIGNALS, AND HEADLIGHTS SOLD AS REPLACEMENT LAMPS FOR USE ON CERTAIN PASSENGER VEHICLES LISTED ABOVE. SOME COMBINATION LAMPS THAT ARE NOT EQUIPPED WITH AMBER SIDE REFLECTORS FAIL… Remedy: PRO-A MOTORS WILL NOTIFY OWNERS AND OFFER TO REPURCHASE THE LAMPS. THE RECALL BEGAN ON APRIL 3, 2006. OWNERS MAY CONTACT PRO-A MOTORS AT 323-838-2988.

93V083000Electrical System:Ignition:SwitchReported 11/05/1993

SALT CORROSION PRODUCTS BETWEEN THE STARTER SOLENOID WIRE AND THE ADJACENT BATTERY FEED IN THE BULKHEAD CONNECTOR MAY SHORT THESE CONNECTIONS, CAUSING THE CIRCUIT TO BYPASS THE IGNITION KEY CONTROL OF THE STARTER MOTOR… Remedy: THE STARTER SOLENOID WIRING WILL BE SEPARATED FROM THE BATTERY FEED WIRE BY RELOCATING IT WITHIN THE BULKHEAD CONNECTOR ON AFFECTED VEHICLES.

Technical service bulletins NHTSA · verified

Showing 5 of 10 bulletins on record with NHTSA.

BulletinDateComponentSummary
D-20-02 Rev. A2020-03-04EquipmentDIPAP Requirements - Addition of Jeep Wrangler (JL/JK) and Jeep Gladiator (JT) Hard Top…
0800600REV2000-12-29Electrical SystemSUBJECT REGARDING WIRE SPLICE REPAIRS. *SB
0806002000-02-25Electrical SystemTHIS BULLETIN PROVIDES A REVISED WIRE SPLICE PROCEDURE AND RELATED PARTS. *TT
1107981998-12-11Engine And Engine CoolingOUTER EXHAUST MANIFOLD STUDS MAY FATIGUE/BREAK. *AK
1107981998-07-31Engine And Engine CoolingTHE OUTER EXHAUST MANIFOLD STUDS MAY FATIGUE AND BREAK. *YC

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 Wrangler. 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.

Reference guides

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

Frequently asked

How much oil does the 1991 Wrangler take?

4 qt w/ filter of ABOVE 30 degrees F: 20W-40 OR 20W-50 API, ABOVE 0 degrees F: 10W-40 API, BELOW 60 degrees F: 5W-30 API, per the factory manual.

Does the 1991 Wrangler have open recalls?

NHTSA lists 8 recall campaign(s) for this model year. Check your specific vehicle by VIN.