ENGINE AR-PRIMARY 1878016 - Caterpillar

Make sure you read and understand the information in the topics Safety and Cooling System Specifications for all information pertaining to water, antifreeze and supplemental coolant additive requirements before you proceed with maintenance of the cooling system.
The access door for the cooling system filler cap is located on top of the engine enclosure on the left side.
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Slowly loosen filler cap in order to relieve system pressure. Remove the filler cap.
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Remove the access cover for the coolant drain. The cover is located in the front, bottom guard.
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Bottom view
Remove the plug from the drain valve. Install a 12.7 millimeter (.5 inch) pipe into the drain valve. The pipe requires 1/2 - 14 NPTF threads. Clamp a hose to the pipe in order to direct the coolant into a suitable container.
Open the drain valve. Allow the coolant to drain into a suitable container.
Flush the system with water. Flush the system until the draining water is clear. Note: If the cooling system is already using ELC, cleaning agents are not required to be used at the specified coolant change interval. Cleaning agents are only required if the system has been contaminated by the addition of some other type of coolant or by cooling system damage. Clean water is the only cleaning agent that is required when ELC is drained from the cooling system.
Close the drain valve and install the plug.
Replace the access cover.
Add the ELC solution. Refer to Operation and Maintenance Manual, "Capacities - Refill".
Start the engine. Run the engine without the filler cap until the thermostat opens and the coolant level stabilizes. Check the level of the coolant. Refer to Operation and Maintenance Manual, "Cooling System Coolant Level - Check".
If the gasket is damaged, replace the filler cap. Install the filler cap.
Stop the engine.
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Clean the radiator cores with compressed air. You may need to use water in order to remove debris. For additional information about the coolant, see Operation and Maintenance Manual, SEBU6250, "Caterpillar Machine Fluids Recommendations" or consult your Caterpillar dealer.