A Camry with a 1MZ-FE engine is equipped with a closed-type cooling system with forced circulation of coolant and a thermostat with a bypass valve in the coolant inlet pipe

The thermostat with bypass valve is located at the inlet of the coolant pump.

Fig. 1. 1MZ-FE engine cooling system and system operation principle: 1 - coolant pump, 2 - cooling system outlet pipe, 3 - bypass channel, 4 - intake manifold, 5 - thermostat, 6 - cylinder block, 7 - radiator

The cooling system includes: a cooling jacket (in the cylinder block and in the cylinder head), a radiator, a coolant pump, a thermostat and an electric cooling fan.

The coolant heated in the cooling jacket is pumped into the radiator by a pump, where it is cooled by the air flow created by the fan and the oncoming air flow that occurs when the vehicle is moving.

Then the coolant is returned to the cooling jacket by means of a pump and cools the engine.

Cooling system radiator

The radiator is located in front of the car and is designed to cool the liquid.

The coolant, heated when passing through the cooling jacket, is cooled in the radiator by the air flow sucked in by the electric fan, as well as by the oncoming air flow that occurs when the car is moving.

Models with automatic transmission have a special automatic transmission fluid cooler located in the lower radiator tank.

At the back of the heatsink is an electrically driven fan.

The fan will only turn on when the coolant temperature reaches the operating temperature.

This reduces the power consumption of the fan drive and prevents motor overcooling.

Expansion tank of the cooling system

Toyota Camry 1MZ-FE cooling system

The expansion tank is designed to accumulate excess coolant volume, which is obtained as a result of its expansion when heated.

When the coolant temperature drops, the coolant returns from the expansion tank to the radiator.

Before topping up the coolant, it is necessary to check its level in the expansion tank.

Coolant pump

The coolant pump forces coolant to circulate through the cooling system.

It is installed in front of the cylinder block and is driven from the crankshaft by a timing belt.


Toyota Camry 1MZ-FE cooling system

The thermostat is installed on the inlet pipe of the cooling circuit.

It regulates the circulation of the coolant.

When the coolant temperature is less than 80–84 °С, the thermostat valve is closed and the coolant circulates through a small circuit of the cooling system (without passing through the radiator), which helps to accelerate the engine warm-up process.

When the temperature of the coolant rises, the thermostat valve opens, allowing the coolant to circulate through the large cooling circuit (through the radiator).

In these engine models, the thermostat starts to open at a coolant temperature of 80 - 84 ° C and opens completely at a temperature of about 95 ° C.