Check the accuracy of the water temperature gauge if either of the conditions that follow are found:
* The gauge reads normal, but the engine is too hot and a loss of coolant is found.
* The gauge shows that the engine is hot, but no loss of coolant can be found.
Coolant temperature can also be read on the display screens of the electronic service tool (ECAP or ET)
(1) Plug. (2). Water temperature regulator housing.
Remove plug (1) and install the adapter, seal, and the 8T0470 Thermistor Thermometer Group or the 2F7112 Thermometer. A temperature gauge of known accuracy can also be used to make this check.
Start the engine and run it until the temperature reaches the desired range according to the test thermometer. If necessary, put a cover over part of the radiator or cause a restriction of the coolant flow. The reading on the gauge for water temperature should agree with test thermometer within the tolerance range of the gauge.