TORQUE CONVERTER GP 6T4674 - Caterpillar

All Industrial, Marine And Generator Set EnginesReference: Service Manual SENR3206, "ETR Electric Protection System."Description of Change: New, more accurate coolant temperature contactors are now available for the above engines. The new contactors are more consistent in their actuation temperature than the earlier style contactor. The new contactors can be used in applications where greater contactor accuracy is required. Since the new contactors are being phased in slowly, conventional type contactors will continue to be used. See the section, "Checking Coolang Contactor Accuracy."Adaptable To: The new, precision type coolant temperature contactors are direct replacements for the conventional type contactors as listed in the chart. Checking Coolant Contactor Accuracy
In many applications, the accuracy of the temperature contactor used in an alarm or shutoff system is very important. To accurately check the actuation temperature of a contactor, do not use a static water bath. Actuation temperature will be 10°C (18°F) or above the actual actuation point when the contactor is installed in an engine. Even using an agitated glycol bath can produce a 3 to 5°C (5 to 9°F) error.
In order to provide a rate of coolant flow high enough to insure accuracy, contactors should be checked in a running engine in a location with good coolant flow. Refer to the test procedure described in the reference.