Service BMW 3 Series 318 325 1988 contains maintenance schedule and the repair procedures you need.
The Repair Manual for BMW 3 Series 318 325 contains:
Fundamentals
Lubrication and maintenance
Engine Management-driveability
Engine
Ignition
Fuel System
Cooling System
Exhaust System and Emission controls
Manual transmission and clutch
Automatic Transmission and clutch
Driveshaft and final drive
Brakes
Suspension and Steering
Body and interior
Electrical System
Index