1986 Cadillac DeVille Repair Manual

The 1986 Cadillac DeVille is a full-size luxury sedan featuring front-wheel drive, V8 engine options including the 4.1L HT-4100, electronic fuel injection, digital instrumentation, automatic climate control, and advanced electronic systems. This repair manual covers comprehensive maintenance, troubleshooting, and repair procedures for all major systems including engine, transmission, electrical, suspension, brakes, and body components.

Vehicle Specifications

Key specifications for the 1986 Cadillac DeVille including dimensions, capacities, and performance data.

Engine Systems

Comprehensive engine repair and maintenance procedures for the 4.1L HT-4100 V8 engine.

1. Engine removal and installation procedures
2. Cylinder head service and valve adjustment
3. Timing chain and sprocket replacement
4. Fuel injection system diagnosis and repair
5. Cooling system maintenance and radiator service
6. Exhaust system inspection and replacement

WARNING! Always disconnect battery before working on electrical components. Allow engine to cool completely before servicing.

Transmission & Drivetrain

Service procedures for the THM 440-T4 4-speed automatic transmission and front-wheel drive system.

1. Transmission fluid service and filter replacement
2. Shift linkage adjustment procedures
3. Torque converter service and replacement
4. Drive axle and CV joint maintenance
5. Transmission control module diagnosis
6. Transfer case service (if equipped)

CAUTION! Use only Dexron II transmission fluid. Never mix fluid types.

Electrical Systems

• Battery: Maintenance-free 12V, 650 CCA
• Alternator: 80-amp output capacity
• Starter: Direct drive 1.4kW
• Instrumentation: Digital dash with trip computer
• Lighting: Sealed beam headlights, LED warning indicators
• Climate Control: Automatic temperature control system
• Power Accessories: Windows, seats, locks, antenna
• Wiring Diagrams: Complete schematics included

Suspension & Steering

Front MacPherson strut and rear semi-trailing arm suspension service procedures.

Front Suspension: Strut replacement, control arm service, ball joint inspection, stabilizer bar service.

Rear Suspension: Trailing arm bushings, shock absorber replacement, wheel bearing service.

Steering: Power steering pump service, gearbox adjustment, tie rod ends, alignment specifications.

Brake Systems

Power-assisted front disc/rear drum brake system maintenance and repair.

1. Brake pad and shoe replacement procedures
2. Rotor and drum machining specifications
3. Master cylinder service and bench bleeding
4. Brake booster diagnosis and replacement
5. ABS system service (if equipped)
6. Parking brake adjustment

Tip: Always replace brake fluid every 2 years or 30,000 miles.

Body & Interior

Body panel alignment, trim replacement, and interior component service.

1. Door panel removal and window regulator service
2. Seat removal and power seat motor replacement
3. Dashboard component access and removal
4. Carpet and headliner replacement
5. Exterior trim and molding service
6. Paint codes and touch-up procedures
7. Glass replacement and windshield service
8. Weatherstrip and seal replacement

WARNING! Use proper trim removal tools to avoid damage to plastic components.

Maintenance Schedule

Factory recommended maintenance intervals and service procedures.

Diagnostic Procedures

Using factory scan tools and diagnostic procedures for engine and transmission codes.

Safety Precautions

Always use jack stands when working under vehicle. Wear safety glasses. Keep work area clean and organized.

CAUTION! Fuel system pressure must be relieved before servicing fuel injection components.

Troubleshooting Guide

Reset Procedures: ECM reset by disconnecting battery for 10 minutes.

Technical Support: Contact Cadillac technical service bulletins for updated information.