Expansion tank

EXPANSION TANK

The expansion tank supplies the circuit and absorbs the variations in coolant volume due to the changes in engine temperature.

In addition, a special calibrated valve contained in the pressurised cap and a pipe connected to it relieve air from the circuit from the pipe leading from the throttle body.

This valve also acts as a washing function enabling outside air to enter the system to compensate for the vacuum created as the system cools.

1. Pressurised cap
2. Pipe
3. Pressure gauge

REMOVAL/REFITTING

• Drain the engine cooling system (see relative paragraph).

1. Loosen the two clamps and disconnect the coolant delivery and return hoses from the expansion tank.
2. Unscrew the three screws and remove the expansion tank.

1. Expansion tank
2. Clamp

ENGINE COOLING SYSTEM LEAK TEST

• Slacken and remove the pressurised cap from the header tank.

1. Screw the instrument for the hydraulic circuit leak test with the special fitting on the header tank filler.
2. Manually pressurise the circuit and check on the instrument that the pressure stays within the specified limit. If not, check for leaks from the sleeves or radiator.

Hydraulic circuit control pressure
1.08 bar

WARNING: During these checks with the tester, for safety reasons, never allow the pressure to exceed 1.38 bar.

PRESSURIZED CAP SEALING TEST

• Perform the test using a seal test tool.

1. Screw the fitting to the lower end of the test tool.
2. Install the expansion tank pressurized cap onto the fitting of the test tool.
3. Manually operate the piston of the test tool and pressurize the cap. Check that the valve opens at the specified pressure read from the manometer.

1. Expansion tank
2. Test tool

Pressurized cap setting
0.98 ± 0.1 bar