C9.3 Marine Auxiliary and Generator Set Engine Caterpillar

Coolant Temperature Is Low

Usage:

C9.3 C93

Use this procedure to troubleshoot a low coolant temperature. Also, use this procedure if one of the following event codes is active or logged.

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Table 1
J1939 Code and Description	Comments
110-17 Engine Coolant Temperature : Low - least severe (1)	The coolant temperature did not rise above a temperature threshold after an extended period of operation under load.

Probable Causes

Jacket water heater
Sensor
Connectors and wiring
Temperature regulators

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Personal injury can result from hot coolant, steam and alkali.
At operating temperature, engine coolant is hot and under pressure. The radiator and all lines to heaters or the engine contain hot coolant or steam. Any contact can cause severe burns.
Remove filler cap slowly to relieve pressure only when engine is stopped and radiator cap is cool enough to touch with your bare hand.

Cooling System Conditioner contains alkali. Avoid contact with skin and eyes.

Recommended Actions

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Table 2
Troubleshooting Test Steps	Values	Results
1. Check for Codes A. Connect Cat^® Electronic Technician (ET) to the service tool connector. B. Look for active codes that are associated with the system for the event code.	Codes	Result: An associated code is active. Repair: Troubleshoot any associated codes before continuing with this test. Result: A code is active or logged. Proceed to Test Step 2.
2. Check the Water Temperature Regulators Note: The water temperature regulators should not begin to open until jacket water reaches opening temperature for the regulators. A. Allow the engine to cool and then start the engine. Check the hose at the outlet for the jacket water. If the hose is warm and normal operating temperature is not achieved yet, a regulator may be stuck open. B. If the water temperature regulators are malfunctioning, check the water temperature regulators. Refer to Testing and Adjusting, "Testing the Cooling System" for additional information.	Regulators	Result: The temperature regulators are NOT OK. Repair: Replace the water temperature regulators. Verify that the repair eliminated the problem. If the problem is not resolved, proceed to Test Step 3.
3. Check the Coolant Temperature Sensor Note: The sensor may be indicating an incorrect temperature that is within the normal range of the sensor. A. Connect Cat ET. B. Use Cat ET to monitor the following temperature: - Coolant temperature Note: The temperature should rise steadily as the engine is warmed. C. Ensure that the temperature is reasonable. D. Reference the reading to another temperature indicator when possible. Refer to Testing and Adjusting, "Testing the Cooling System" for additional information.	Sensor	Result: The temperature sensor is OK. Proceed to Test Step 4. Result: The temperature sensor is NOT OK. Proceed to Test Step 4.
4. Inspect the Electrical Connectors and the Wiring A. Turn the main disconnect switch to the OFF position. B. Thoroughly inspect the connectors. Refer to Troubleshooting, "Electrical Connectors-Inspect" for additional information. C. Perform a 45 N (10 lb) pull test on the connector wires. D. Check the harness for abrasions and pinch points.	Connectors and Wiring	Result: The connectors and wiring appear to be OK. Repair: Replace the sensor. Verify that the repair eliminated the problem. Result: There is a problem with the connectors and/or wiring. Repair: Repair or replace the connectors or wiring. Ensure that all the seals are properly in place and ensure that the connectors are coupled. Verify that the repair eliminated the problem.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).