1988 Cadillac Sedan DeVille Repair Manual

The 1988 Cadillac Sedan DeVille is a full-size luxury sedan featuring front-wheel drive, 4.1L or 4.5L V8 engines, 4-speed automatic transmission, electronic fuel injection, digital instrumentation, climate control, power accessories, and advanced suspension systems. This manual covers maintenance, troubleshooting, and repair procedures for engine, transmission, electrical, brakes, suspension, and body components.

1. Vehicle Specifications 2. Maintenance Schedule 3. Engine Systems 4. Transmission 5. Electrical System 6. Brake System 7. Suspension & Steering 8. Body & Interior 9. Troubleshooting Guide 10. Safety Precautions 11. Technical Service Bulletins

Vehicle Specifications

Key technical data for the 1988 Cadillac Sedan DeVille.

Component	Specification
Engine	4.1L V8 (HT-4100) or 4.5L V8
Horsepower	130-155 hp
Transmission	4-speed automatic (4T60)
Fuel System	Electronic Fuel Injection
Brakes	Front disc, rear drum with ABS
Suspension	Independent front, beam axle rear
Wheelbase	113.8 inches
Fuel Capacity	18 gallons
Curb Weight	Approx. 3,500 lbs
Oil Capacity	4.5 quarts with filter

Maintenance Schedule

Recommended service intervals for optimal performance.

Oil Change: Every 3,000 miles or 3 months
Filter Replacement: Air filter every 15,000 miles, fuel filter every 30,000 miles
Tire Rotation: Every 6,000 miles
Brake Inspection: Every 12,000 miles
Coolant Flush: Every 30,000 miles or 2 years
Transmission Service: Every 50,000 miles
Timing Belt: Inspect every 60,000 miles

WARNING! Always use manufacturer-recommended fluids and parts. Disconnect battery before electrical work.

Engine Systems

Procedures for engine maintenance and repair.

Spark Plug Replacement: Gap 0.045 inches, torque 15 ft-lbs
Ignition Timing: Set to 15° BTDC with timing connector disconnected
Fuel System: Check fuel pressure (9-13 psi), replace filter if clogged
Cooling System: Check thermostat operation, flush radiator annually
Belt Tension: Adjust serpentine belt to 1/2 inch deflection
Compression Test: Should read 120-150 psi across all cylinders

CAUTION! Allow engine to cool before opening cooling system. Relieve fuel pressure before fuel line work.

Transmission

Type: 4T60 4-speed automatic with overdrive
Fluid Type: Dexron II or III ATF
Fluid Capacity: 7.5 quarts (pan drop)
Filter Service: Replace with fluid change
Shift Points: 1-2: 15 mph, 2-3: 25 mph, 3-4: 45 mph
TV Cable Adjustment: Critical for proper shift timing
Neutral Safety Switch: Located on transmission case

Electrical System

Diagnosis and repair of electrical components.

Battery: 12V, 650 CCA, negative ground. Alternator: 100 amp output. Starter: Direct drive type.

Fuses: Located in under-dash panel and under-hood center. Relays: Fuel pump, cooling fan, horn. Wiring: Color-coded diagrams available in separate section. Digital Dash: Check grounds and power supply modules for instrument issues.

Brake System

Hydraulic brake system maintenance and repair.

Pad Replacement: Front disc pads wear indicator at 1/8 inch
Rotor Specification: Minimum thickness 1.230 inches
Brake Fluid: DOT 3, flush every 2 years
Bleeding Sequence: Right rear, left rear, right front, left front
Parking Brake: Adjust at equalizer under vehicle
ABS Diagnosis: Check wheel sensors and control module

Tip: Always replace brake components in axle sets.

Suspension & Steering

Front and rear suspension service procedures.

Strut Replacement: Requires spring compressor tool
Ball Joints: Check for play with wheels off ground
Tie Rod Ends: Replace if steering play exceeds 1/4 inch
Wheel Alignment: Camber: -0.5° to +0.5°, Toe: 0° to +0.2°
Power Steering: Use Dexron ATF, check pump pressure
Stabilizer Links: Replace if bushings are cracked or worn

WARNING! Use proper spring compression tools. Never heat suspension components.

Body & Interior

Repair and maintenance of body panels and interior components.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
Engine cranks but won't start	Fuel pump, ignition module	Check fuel pressure, spark, ignition control module
Transmission slips	Low fluid, TV cable	Check fluid level, adjust TV cable, pressure test
Electrical drain	Alternator, short circuit	Perform parasitic draw test, check diode trio
Brake pulsation	Warped rotors	Resurface or replace rotors, check calipers
Overheating	Thermostat, water pump	Test thermostat, check water pump flow
Poor fuel economy	O2 sensor, filters	Replace O2 sensor, air filter, check tire pressure

Safety Precautions

Always use jack stands when working under vehicle. Disconnect battery before electrical repairs. Use eye protection when using impact tools. Properly dispose of fluids and batteries.

CAUTION! Fuel injection systems maintain high pressure - relieve pressure before service.

Technical Service Bulletins

Common manufacturer-issued updates: Transmission shift improvements, digital dash display fixes, fuel injection calibration updates, brake component revisions. Contact Cadillac dealer for specific TSB applications to your VIN.