Toyota Land Cruiser 100/Amazon, Lexus LX 470

since 1997 release

Repair and operation of the car

Cooling systems of the engine, heating of salon and air conditioning

General information

Engine cooling system

Scheme of circulation of cooling liquid (engine 2UZ-FE)

All models of the cars considered in the present manual are equipped with the engine cooling system working with an excessive pressure with thermostatic management of circulation of working liquid. The water pump of rotor type is fixed on the block of the engine and provides pumping of cooling liquid through a cooling path of the last. The stream of liquid washes regions of an arrangement of each of cylinders in the block then goes to back part of the engine. The cooling channels laid in molding of the block and a head of cylinders provide intensive cooling of inlet and final ports, areas of installation of spark plugs and the directing plugs of final valves (address to an illustration above). The pump fastens to the block and access to it opens after dismantle of a forward cover and a gas-distributing belt.

The Voskozapolnenny thermostat controls the working temperature of the engine in the course of its warming up. The first minutes after start of the cold engine the thermostat remains closed, preventing thereby circulation of cooling liquid through a radiator. In process of approach of temperature of the engine to normal working value, the thermostat valve gradually opens, connecting to a cooling contour the radiator providing the maximum intensity of the heat sink from a working body (cooling liquid).

The cooling system has a tight design and is densely closed by the cover of a radiator capable to maintain a certain excessive pressure that provides increase of a boiling point of cooling liquid and, respectively, efficiency of the heat sink through a radiator. At excess by internal pressure in system of some certain value, the sprung plate of the radiator of the safety valve which is built in in a cover rises over the saddle, providing an overflowing of excess of cooling liquid on a connecting (overflow) tube in a broad tank. In process of cooling of system liquid automatically comes back from a tank to a radiator.

In view of the listed features of a design, such cooling system received the name closed as in it any functional losses of a working body are excluded.

System of heating

The main components of system of heating of salon are the electric fan and the heat exchanger placed in the box-shaped casing of a heater fixed under the car dashboard. The heat exchanger by means of rubber hoses is connected to the engine cooling system. On some models the back heater of salon located under the right forward seat is established. The control unit of functioning of the heater/conditioner of air is built in in the car dashboard. The cooling liquid warmed in the engine circulates via the heater heat exchanger, giving the to the air which is warmly filling a casing. At inclusion of heating of salon there is an opening of the lamellar gate therefore the internal volume of a casing of a heater connects to the volume of salon. At turning on of the fan the krylchatka of the last starts banishing the air given to salon via the heat exchanger, providing its intensive warming up.

Air conditioning system

The condenser installed ahead of a radiator, the evaporator, close to the heater heat exchanger fixed on the engine block the compressor, and filtering a receiver dehumidifier (accumulator) equipped with the reducing valve of a high pressure are a part of central air. All components are connected among themselves by refrigerator lines.

The fan banishes the air coming to salon through the evaporator heat exchanger working in the mode, the return to the mode of functioning of a radiator. The coolant which is pumped over via the heat exchanger begins to boil and, evaporating, selects at air surplus of heat. Temperature in salon thus decreases to the demanded comfortable value (at the choice of the operator). The compressor supports circulation of coolant in system, pumping over the warmed liquid via the condenser where it is cooled and comes back to the evaporator.