InfinitiQ451991Overview/infiniti/q45/1991/base/

1991 Infiniti Q45

Factory specifications, fluid capacities, torque values, EPA fuel economy and the federal safety record for the 1991 Q45.

Transmission Automatic 4-spd

The 1991 Infiniti Q45 is equipped with a 4-speed automatic transmission and utilizes 6.3 quarts of 5W-30 or 10W-30 API SM engine oil. With an EPA rating of 15/20/17 mpg, this model year represents the highest volume of owner complaints in the vehicle's 1990-2006 history. These 47 complaints, along with two recalls, center primarily on the hydraulic service brakes.

Model year200620052004200320022001199919981991

Quick specs

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

Engine oil capacity6.3 qtOEM · verified
Engine oil type5W-30 / 10W-30 API SMOEM · verified
EPA fuel economy15/20/17 mpgEPA · verified

Full specifications

Engine, drivetrain, dimensions and economy.

Engine & drivetrain NHTSA vPIC

TransmissionAutomatic 4-spd

Dimensions & weight NHTSA vPIC

Overall length200 in
Overall width72 in
Overall height56.3 in
Wheelbase113.4 in
Curb weight3951 lb
Weight distribution (front / rear)57/43

Ratings & economy EPA / vPIC

EPA city / highway / combined15 / 20 / 17 mpg
DrivetrainRear-Wheel Drive
Passenger volume95 cu ft
Cargo volume15 cu ft
Recommended fuelPremium Gasoline

Performance & power Independent road tests

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

Independent road tests for the Q45 of this era, listed by trim and engine — this page spans more than one engine, so no single horsepower figure is shown.

7.3 sec0–60 mph (tested)quickest 7.30 sec — 1991 t Sedan
YearTrim / engine0–60¼ mileHPDrivetrain
1991t Sedan 4.5L V87.30 sec15.60 sec278 hpRWD
1990Sedan 4.5L V86.90 sec15.40 sec278 hpRWD
1990Sedan 4.5L V87.20 sec15.30 sec278 hpRWD
1990Sedan 4.5L V87.90 sec15.80 sec278 hpRWD
1994t Sedan 4.5L V88.20 sec16.30 sec278 hpRWD
1995a Sedan (Full-Active Suspension) 4.5L V87.80 sec16.10 sec278 hpRWD
1995t Sedan 4.5L V87.90 sec16.20 sec278 hpRWD

Service quick specs OEM factory data

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

This engine holds 6.3 qt of 5W-30 / 10W-30 API SM engine oil, 75W-90 · 80W-90 · GL-5 in the differential, DOT 3 brake fluid.

Lubricants & capacities

Brake FluidDOT 3
Differential Gear Oil75W-90 · 80W-90 · GL-5
Differential Gear Oil Capacity3.1 Pints
Engine CoolantETHYLENE GLYCOL
Engine Oil5W-30 · 10W-30 · API
Engine Oil Capacity6.3 qt
Power Steering FluidATF

Factory maintenance schedule OEM · verified

Normal service, condensed from the factory interval matrix.

Under the factory schedule, replace the engine oil and filter at 7,500 mi; spark plugs every 60,000 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 7,500 miEngine Oil Filter (replace)
Every 7,500 miBattery (inspect electrolyte level) · Engine Oil (drain & refill) · Tire & Wheel Assembly (rotate)
Every 15,000 miAccessory Drive Belt (inspect) · Brake System (inspect) · Differential (inspect fluid level) · Engine Oil Filter (replace) · Exhaust System (Complete) (inspect)
Every 30,000 miEngine Air Filter Element (replace) · Engine Coolant System (drain, flush & refill) · Fuel Evaporative Emission Control System Lines (inspect) · Fuel Line (inspect) · PCV Hose (inspect) · Steering Linkage (inspect)
At 60,000 miAccessory Drive Belt (inspect) · Engine Coolant System (drain, flush & refill)
Every 60,000 miActive Suspension System (drain & refill) · Spark Plugs (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 1991 Infiniti Q45 sits at the top of a problem spike in the model's early run. Complaints jump to 47 from 1990's 33, recalls double from 1 to 2, and investigations triple from 1 to 3, while 1992 immediately reverses course with 29 complaints, 1 recall, and 0 investigations. That makes 1991 the clear outlier year for this first-generation stretch, with the highest complaint volume before activity settles into the single digits and low teens seen from 1993 onward. Its leading complaint categories are service brakes/hydraulic (8), equipment (7), electrical system (7), and engine/engine cooling (4), with 3 crash-related and 4 fire-related complaints on the federal record. Because 1991 carries the worst early-year counts for complaints, recalls, and investigations in this dataset, it is not the strongest candidate among first-generation Q45s.

2
Open recalls
NHTSA campaigns
30
Service bulletins
Manufacturer communications
3
ODI investigations
Office of Defects Investigation
47
Owner complaints
3 involved a crash · 4 a fire
NHTSA crash-test rating federal NCAP · out of 5 stars
Rollover★★★★★
Owner complaints by model year NHTSA · this generation & adjacent

Owner complaints filed with NHTSA, by component

All 47 complaints on record, top 8 components.

Service Brakes, Hydraulic8
Equipment7
Electrical System7
Engine & Engine Cooling4
Suspension4
Power Train3
Visibility3
Air Bags2

Source: NHTSA Office of Defects Investigation complaint database.

Recalls NHTSA · verified

Showing 2 of 2 campaigns on record for this vehicle.

98V284000Equipment:Electrical:Radio/Tape Deck/Cd Etc.Reported 05/11/1998

VEHICLE DESCRIPTION: PASSENGER VEHICLES EQUIPPED WITH BOSE REAR SPEAKERS THAT HAVE AN INTEGRAL AMPLIFIER. A CONDUCTIVE BRIDGE CAN FORM BETWEEN TWO LINES OF THE CIRCUIT BOARD PATTERN WHEN THERE IS ACCUMULATED ELECTROLYTE… Remedy: DEALERS WILL REPLACE THE CIRCUIT BOARD WITH A NEW BOARD THAT HAS BEEN COATED.

95V103002Seat Belts:Front:Buckle AssemblyReported 24/05/1995

THE FRONT SAFETY BELT BUCKLE RELEASE BUTTONS CAN BREAK. THESE RED PLASTIC RELEASE BUTTONS ARE MARKED "PRESS." IF A BUTTON BREAKS, PIECES CAN FALL INTO THE BUCKLE ASSEMBLY CAUSING THE BUCKLE TO OPERATE IMPROPERLY. Remedy: OWNERS SHOULD PROMPTLY CHECK THE CONDITION AND OPERATION OF BOTH FRONT SAFETY BELT BUCKLES AND CAREFULLY INSPECT THE RED RELEASE BUTTON FOR ANY BREAKS OR CRACKS. THEY SHOULD…

Technical service bulletins NHTSA · verified

Showing 5 of 30 bulletins on record with NHTSA.

BulletinDateComponentSummary
ITB13-007H2023-02-27StructureREMOVING FOREIGN MATERIAL FROM THE WINDOW GLASS This bulletin has been amended. See…
ITB09-039J2023-02-27VisibilityWINDSHIELD CRACKING This bulletin has been amended. See AMENDMENT HISTORY on the last…
ITB10-067C2023-02-22WheelsWHEEL BEARING COLLISION DAMAGE This bulletin has been amended. See AMENDMENT HISTORY on…
ITB16-006A2021-03-24Electrical SystemINFINITI; FRONT SONAR PARKING SENSOR SERVICE INFORMATION This bulletin has been amended…
ITB19-0082019-04-02EquipmentEXTERIOR CLEANING INFORMATION SERVICE INFORMATION When cleaning the exterior of an…

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 Q45. 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 Q45 take?

6.3 qt of 5W-30 OR 10W-30 API SM, per the factory manual.

Does the 1991 Q45 have open recalls?

NHTSA lists 2 recall campaign(s) for this model year. Check your specific vehicle by VIN.

What gas mileage does the Q45 get?

EPA figures are 15 city / 20 highway / 17 combined mpg.