E 500 (211.070) V8-5.0L (113.967) (2004)
Thermostat: Testing and Inspection
Test Coolant Thermostat
DANGER:
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Risk of injury to skin and eyes suffering scalding from contact with hot coolant spray. Risk of poisoning from swallowing coolant.
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Do not open cooling system unless coolant temperature is below 90 degrees C. Open cap slowly and release the pressure. Do not pour
coolant into beverage bottles.
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Wear protective gloves, protective clothing and eye protection.
1
Remove coolant thermostat (1)
NOTE: Installation:
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Install new sealing ring.
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The coolant thermostat must not be removed from the housing. Otherwise it will be destroyed. The housing is supplied together with the
coolant thermostat for repair purposes.
Inspection
2
Heat coolant thermostat (1)
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Suspend coolant thermostat (1) from a wire in a vessel filled with water and heat the water.
CAUTION: For heating on no account use a welding torch or soldering torch as the sudden introduction of heat alters the structure of
the metal!
3
Measure temperature of water
NOTE: The heating-up rate should be not more than 1 degrees C to 2 degrees C/min from about 8 degrees C below the start of opening of the
coolant thermostat.
4
Heat water to the fully open temperature of the thermostat (2) and then measure the stroke
NOTE: If the test values are not achieved, install a new coolant thermostat.
5
Install in the reverse order
6
Inspect cooling system for leaks.