Test coolant thermostat

AR20.10-T-2455BB

21.3.01

ENGINE 457.941 in MODELNMB613.368

ENGINE 457.942 in MODEL NMB671.015 /020 /021 /030 /042 /332 /333

ENGINE 457.944 in MODEL NMB613.358 /367 /388

W20.10-0005-04

1 Coolant thermostat

1/1 Main valve

1/2 Short circuit valve

	Inspect
 Danger!	Risk of injury to skin and eyes from 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)	On model 613.358/388, model 671	AR20.10-T-2460BB
		On model 613.367	AR20.10-T-2460CB
		On model 613.368	AR20.10-T-2460CA
2	Suspend coolant thermostat (1) in a vessel filled with water
3	Check start of opening of coolant thermostat (1)	 Heat up water slowly and stir in order to distribute the heat evenly. Reduce the rate at which the water is heated up to 1 - 2 °C/min about 8 °C before the start of opening is reached. The coolant thermostat (1) must open visibly as soon as the temperature of the start of opening is reached.	*BE20.10-N-1001-02G
4	Check full opening of coolant thermostat (1)	 The main valve (1/1) must have reached the full opening in 6 to 8 minutes after the start of opening if an even temperature rise is maintained.
5	Determine temperature of water and stroke of main valve (1/1)	 Only carry out the measurement when main valve is fully open. If the test valuess are not maintained, the coolant thermostat (1) has to be replaced.	*BE20.10-N-1002-02G
6	Install coolant thermostat (1)	On model 613.358/388, model 671	AR20.10-T-2460BB
		On model 613.367	AR20.10-T-2460CB
		On model 613.368	AR20.10-T-2460CA

Test specifications of coolant thermostat

Number	Designation			Engine 457.9


BE20.10-N-1001-02G	Coolant thermostat	Start of opening	°C	83 (2)
BE20.10-N-1002-02G	Coolant thermostat - main valve	Fully open	°C	95
		Stroke	mm	8