Check coolant thermostat

AR20.10-G-2455B

Check coolant thermostat

9.1.12



Checking

 Danger!

Risk of injury to skin and eyes caused by handling hot or glowing objects.

Wear safety gloves, protective clothing and safety glasses, if necessary.

AS00.00-Z-0002-01A

1

Remove coolant thermostat (1)

Engine 900, 902, 904, 906, 924

AR20.10-G-2460B

Engine 926

AR20.10-G-2460F

2

Suspend coolant thermostat (1) from a wire in a vessel filled with water

3

Warm water using a suitable heart source and constantly measure water temperature using a temperature measuring device

 On no account use a welding torch or soldering torch to heat the coolant thermostat (1). The coolant thermostat (1) can get damaged otherwise.

 Stir water so that the temperature of the water is the same at all points

The heat-up rate should be not greater than 1 to 2°C/min. from approx. 8°C below the temperature at which the main valve (1/1) begins to open

*BE20.10-N-1001-02J

4

Determine start of opening of main valve (1/1)

 When opening the main valve (1/1) compare the indicated actual value on the temperature measuring device with the specified value. Replace coolant thermostat (1) if the specified value is not reached.

*BE20.10-N-1001-02J

5

Continue to warm up the water until bypass valve (1/2) is closed

Engines 900, 904, 924, 926

 When closing bypass valve (1/2) compare indicated actual value on temperature measuring device with the specified value. Replace coolant thermostat (1) if the specified value is not reached.

*BE20.10-N-1003-02J

6

Continue to warm up water until the main valve (1/1) is fully opened

 For a fully opened main valve (1/1) compare indicated actual value on temperature measuring device with the specified value. Replace coolant thermostat (1) if the specified value is not reached.

*BE20.10-N-1002-02J

7

Remove coolant thermostat (1) from vessel and measure distance between collar on coolant thermostat (1) and plate of main valve (1/1)

 Measurement must take place immediately after removing the coolant thermostat (1) from the vessel.

Note the measured value.

8

Allow coolant thermostat (1) to cool down

 Allow coolant thermostat (1) to cool off until main valve (1/1) is closed

9

Measure distance between collar on coolant thermostat (1) and main valve (1/1) plate

 With the aid of this measured value and the previously noted measured value calculate the actual value for the stroke of the main valve (1/1). Replace coolant thermostat (1) if the specified value is not reached.

*BE20.10-N-1002-02J

10

Install coolant thermostat (1)

Engine 900, 902, 904, 906, 924

AR20.10-G-2460B

Engine 926

AR20.10-G-2460F

Number

Designation

Engine
900.91/92, 902.92/93, 904.92/95,
906.935/95, 924.91/92/93

Engine
926.969

BE20.10-N-1001-02J

Coolant thermostat start of opening

°C

83 (2)

83 (2)

BE20.10-N-1002-02J

Coolant thermostat main valve

Full opening

°C

95

95

Stroke

mm

8

8

BE20.10-N-1003-02J

Coolant thermostat bypass valve closed at

°C

92

92