C13 Engines for Caterpillar Built Machines Caterpillar

Coolant Temperature Is Low

Usage:

Use this procedure to troubleshoot a low coolant temperature. Refer to Troubleshooting, "Event Codes" for information about event codes.

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Table 1

CDL Code	Code Description (code descriptions may vary)	Comments
E199 (1)	Engine Coolant Temperature : Low - least severe (1)	The coolant temperature did not rise above 65° C (149° F) after an extended period of operation under load.

Probable Causes

Thermostat
Coolant temperature sensor
Extreme ambient temperatures
Engine cooling fan configuration

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in order.

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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.

Complete the procedure in the order in which the steps are listed.

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Table 2
Troubleshooting Test Steps	Values	Results
1. Make Sure the Engine is Properly Equipped for Ambient Conditions A. Ensure that the engine is properly equipped for the ambient conditions. Refer to the Owners Manual for operation in cold ambient conditions.	Engine Operation	Result: The engine is equipped for the ambient conditions. Proceed to Test Step 2. Result: The engine is not equipped for ambient conditions. Repair: Refer to the Owners Manual for more information regarding equipment required for cold-weather operation.
2. Inspect the Cooling System A. Check the coolant level. B. Check for signs of a coolant leak.	Engine Coolant Level	Result: The engine coolant level is OK. Proceed to Test Step 3. Result: The engine coolant level is not OK. Repair: Check the cooling system for leaks. Refer to Troubleshooting, "Coolant Level is Low" for additional information. Repair any leaks.
3. Faulty Coolant Temperature Sensor A. Check the reading of the coolant temperature on Cat ET. The temperature should rise steadily as the engine is warmed. Ensure that the temperature is reasonable.	Faulty Coolant Temperature Sensor	Result The coolant temperature is not reasonable. Repair: A failed coolant temperature sensor has been detected. Replace the temperature sensor. Result The coolant temperature is reasonable. Proceed to Test Step 4.
4. Check the Engine Coolant System A. Turn the keyswitch to the OFF position. B. Connect to Cat ET. C. Start the engine. D. Monitor the "Engine Coolant Temperature" in the status screen E. Ensure the engine cooling fan is properly configured for the ambient conditions. F. Ensure that the engine cooling fan is operation properly.	Coolant Temperature	Result: The coolant temperature comes up to operational temperature and the engine fan is functioning properly. Return the unit to service. Result The coolant temperature does not come up to operational levels and the engine fan is functioning properly. Repair: A failed thermostat has been detected. Replace the thermostat. Result The coolant temperature does not come up to operational levels due to the engine fan running continuously. Repair: Refer to Troubleshooting, "Cooling Fan Is Always ON".