Toyota Tacoma 1995-2004, 4Runner 1996-2002, T100 1993-1998 Repair Manual

All vehicles covered by this manual employ a pressurized engine cooling system with thermostatically controlled coolant circulation. An impeller type water pump mounted on the front of the block pumps coolant through the engine. The coolant flows around each cylinder and toward the rear of the engine. Cast-in coolant passages direct coolant around the intake and exhaust ports, near the spark plug areas and in proximity to the exhaust valve guides. The four-cylinder engines are designed with the water pump mounted directly on the timing cover while the V6 engines are mounted on the block and require timing belt cover and timing belt removal.

A wax-pellet type thermostat is located in the thermostat housing at the radiator end of the engine. During warm up, the closed thermostat prevents coolant from circulating through the radiator. When the engine reaches normal operating temperature, the thermostat opens and allows hot coolant to travel through the radiator, where it is cooled before returning to the engine.

The cooling system is sealed by a pressure-type radiator cap. This raises the boiling point of the coolant, and the higher boiling point of the coolant increases the cooling efficiency of the radiator. If the system pressure exceeds the cap pressure-relief valve, the excess pressure in the system forces the spring-loaded valve inside the cap off its seat and allows the coolant to escape throught the overflow tube into a coolant reservoir. When the system cools, the excess coolant is automatically drawn from the reservoir back into the radiator.

The coolant reservoir serves as both the point at which fresh coolant is added to the cooling system to maintain the proper fluid level and as a holding tank for overheated coolant.

This type of cooling system is known as a closed design because coolant that escapes past the pressure cap is saved and reused.

• Introduction: Vehicle identification numbers; Buying parts; Maintenance techniques, and more.
• Tune-up and routine maintenance
• Four-cylinder engines
• V6 engines
• Engine and overhaul procedures
• Cooling, heating and air-conditioning systems
• Fuel and exhaust systems
• Engine electrical systems
• Emissions control systems
• Manual transmission
• Automatic transmission
• Transfer case
• Clutch and driveaxles
• Brakes
• Suspension and steering systems
• Body
• Chassis electrical system
• Wiring diagrams