Toyota 12R & 2R Engine Repair Manual

Quick guide from the manual

This manual provides comprehensive service and repair procedures for the Toyota 12R and 2R engines. It is intended for use by trained mechanics and includes detailed specifications, troubleshooting tables, and step-by-step repair instructions.

General Information

The 2R and 12R engines are four-cylinder, overhead valve square type engines. This section covers engine construction, general specifications, and recommended special service tools. Always use fender and seat covers when working on a customer's vehicle to prevent damage.

Engine Tune-up

Periodic tune-ups are essential for maintaining performance. Key procedures include:

• Battery: Inspect specific gravity and electrolyte levels.
• Engine Oil: Check level and condition; replace if dirty.
• Coolant: Check for leaks and proper level.
• Fan Belt: Check tension (8-13 mm deflection with 10 kg pressure).
• Spark Plugs: Inspect for wear, clean, and adjust gap to 0.8 mm (0.031").
• Distributor: Clean cap, check rotor, and adjust ignition timing (8° B.T.D.C. at 550 rpm).
• Valve Clearance: Adjust to 0.203 mm (0.008") for intake and 0.360 mm (0.014") for exhaust.

Major Service

This section details the removal, disassembly, inspection, and assembly of the engine. Key steps include:

• Removal: Follow specific sequences for RT/RN and RH/RY series vehicles.
• Disassembly: Stamp mating marks on parts like the clutch cover and flywheel before removal to ensure correct reassembly.
• Inspection & Repair: Clean all parts thoroughly. Check cylinder head warpage, valve seat contact, valve guide bushing clearance, and piston ring end gaps.
• Assembly: Use new gaskets and seals. Follow specified torque settings for all bolts, especially cylinder head and bearing cap bolts.

Troubleshooting

The manual includes detailed tables for diagnosing common issues such as:

• Lack of Power: Check for poor compression, incorrect ignition timing, or fuel system issues.
• Overheating: Inspect coolant level, fan belt, thermostat, and water pump.
• Excessive Oil Consumption: Check for oil leaks, worn piston rings, or worn valve guides.
• Hard Starting: Inspect battery, starter motor, and ignition system.

Systems

The manual provides detailed service information for the following systems:

• Fuel System: Detailed breakdown of the carburetor, fuel pump, and fuel filter. Includes adjustment procedures for float level, idle speed, and automatic choke.
• Lubricating System: Covers oil pump inspection and oil filter maintenance.
• Cooling System: Details on water pump and thermostat service.
• Charging System: Procedures for alternator and regulator testing and adjustment.
• Starting System: Starter motor disassembly, inspection, and testing.
• Ignition System: Distributor service, ignition coil testing, and spark plug specifications.