Pic. 2.16. Engine cooling system 1ZZ-FE AND 3ZZ-FE
Pic. 2.17. Block diagram of the cooling system for engines 1ZZ-FE AND 3ZZ-FE
Closed cooling system with forced circulation.
Includes thermostat with bypass valve; the thermostat is installed in the inlet pipe, through which the coolant enters the engine; it maintains the set operating temperature of the coolant.
To reduce weight, an aluminum radiator is used.
The coolant moves in the cylinder block along a U-shaped contour; thanks to this scheme, the turbulence of the flow is eliminated. In addition, there is a bypass channel between the cylinder head and the cylinder block.
Hot coolant from the cylinder head is supplied to the throttle body, preventing it from freezing.
The cooling system and air conditioning are served by one fan.
Differences from previous models
The cooling system uses Toyota Genuine SLLC Extended Life Coolant. Thanks to this, it was possible to reduce the frequency of maintenance.
Coolant
Extended Drain Coolant (SLLC) is a mixture of 50% coolant concentrate and 50% distilled water. It is not necessary to dilute the coolant when topping up or replacing.
When mixing LLC and SLLC coolants, the change should be made according to the frequency for LLC (every 30,000 km or 24 months, whichever comes first).
When replacing LLC brand coolant with SLLC, subsequent replacements can be made according to the intervals for SLLC (every 80,000 km of run).