Chieks and inspections

CHIEKS AND INSPECTIONS

• Check that the pump body and impeller are in good condition and that there are no signs of oxidation or corrosion.
• Check that the axial clearance "Ga" of the water pump shaft is within the prescribed limits.
• Check that the clearance "Gr" between rotor and pump body is within the specified limits.

1. Aeration hole
2. Impeller
3. Bearing
4. Pump body
5. Drainage hole

• Check that the front gasket of the pump is in good condition and without leaks.
  NOTE: small leaks from the drainage hole of the pump are normal;
• check that the bearing does not show signs of wearing on the races and balis.

If any of these defects are detected, replace the entire pump.

THERMOSTAT UNIT

The thermostat unit is installed on the rear side of the cylinder heads.
It ensures that the engine does not exceed the optimal temperature. Until the temperature of the coolant reaches 87 ± 2°C, the thermostat valve deviates the liquid directly to the pump: at temperatures above this value the opening of the thermostat valve conveys the liquid to the radiator.
The thermostat is provided with a sensor (NTC) which measures the temperature of the coolant and sends it to the Motronic control unit.

REMOVAL/REFITTING

• Remove the negative cable from the battery.

1. Disconnect the electrical connection from the engine coolant temperature sensor (NTC).