PlymouthConquest1985Overview/plymouth/conquest/1985/base/

1985 Plymouth Conquest

Factory specifications, fluid capacities, torque values, EPA fuel economy and the federal safety record for the 1985 Conquest.

Transmission Automatic 4-spd

The 1985 Plymouth Conquest takes 4.5 qt w/ filter of 20W-20 engine oil and is EPA-rated at 17/22/19 mpg city/highway/combined.

Model year19851984

Quick specs

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

Engine oil capacity4.5 qt w/ filterOEM · verified
Engine oil type20W-20 / 15W-40 / 5W-30OEM · verified
EPA fuel economy17/22/19 mpgEPA · verified

Full specifications

Engine, drivetrain, dimensions and economy.

Engine & drivetrain NHTSA vPIC

TransmissionAutomatic 4-spd

Ratings & economy EPA / vPIC

EPA city / highway / combined17 / 22 / 19 mpg
DrivetrainRear-Wheel Drive
Recommended fuelPremium Gasoline

Service quick specs OEM factory data

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

This engine holds 4.5 qt w/ filter of 20W-20 / 15W-40 / 5W-30 engine oil, GL-5 · 80W-90 · 85W-90 in the differential, DOT 3 brake fluid.

Lubricants & capacities

Brake FluidDOT 3
Differential Gear OilGL-5 · 80W-90 · 85W-90
Differential Gear Oil Capacity2.5 Pints
Engine CoolantETHYLENE GLYCOL
Engine Oil20W-20 · 15W-40 · 5W-30 · 5W-40
Engine Oil Capacity4.5 qt w/ filter
Power Steering FluidUSE MOPAR PART NO. 4318055 OR EQUIVALENT

Factory maintenance schedule OEM · verified

Normal service, condensed from the factory interval matrix.

Under the factory schedule, replace the engine oil and filter every 3,000 mi; spark plugs every 30,000 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.

Every 3,000 miEngine Oil (drain & refill)
Every 6,000 miEngine Oil Filter (replace)
Every 7,500 miClutch Master Cylinder (inspect fluid level) · Power Steering System (inspect)
Every 15,000 miAccessory Drive Belt (inspect) · Air Conditioning System (inspect) · Brake System (inspect) · Drive Axle Assembly (drain & refill) · Engine Valves (inspect valve lash) · Exhaust System (Complete) (inspect)
Every 30,000 miAccessory Drive Belt (inspect) · Differential (inspect fluid level) · Engine Air Filter Element (replace) · Engine Coolant System (drain, flush & refill) · Spark Plugs (replace) · Steering Linkage (inspect)
Every 50,000 miAir Injection System (inspect) · Air Intake Duct (inspect) · Engine Coolant System Hoses (inspect) · Fuel Evaporative Canister (replace) · Fuel Evaporative Emission Control System (inspect) · Fuel Evaporative Emission Control System Lines (inspect)
At 60,000 miAccessory Drive Belt (inspect) · Air Conditioning System (inspect)
Every 60,000 miBrake Hydraulic System (drain, refill & bleed) · PCV System (inspect)

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

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Vehicles with shared specs

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Reference guides

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

Frequently asked

How much oil does the 1985 Conquest take?

4.5 qt w/ filter of ABOVE 20 degrees F: 30, 20 degrees F TO 80 degrees F: 20W-20, ABOVE 10 degrees F: 15W-40, BELOW 100 degrees F 5W-30 OR 5W-40, BELOW 60 degrees F: 5W-30, 5W-40, per the factory manual.

What gas mileage does the Conquest get?

EPA figures are 17 city / 22 highway / 19 combined mpg.