3408 TRUCK ENGINE Caterpillar

As Needed

Usage:

(25)Cooling System - Cleaning

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Always inspect the cooling system with the engine stopped.
Remove the radiator cap slowly to relieve pressure. Steam can cause personal injury.

Conditioner contains alkali, avoid contact with skin and eyes to prevent personal injury.

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NOTICE

When changing antifreeze solution, replace the attachment coolant conditioner group maintenance filter element with the appropriate precharge filter element. If Dowtherm is used, use only a 9N3717 Filter Element as a precharge element.

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NOTICE

All water is corrosive at engine operating temperature. Use Caterpillar Cooling System Conditioner liquid, or the attachment coolant conditioner group to treat either plain water or solution. NEVER use both the liquid cooling system conditioner and the coolant conditioner element at the same time.

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NOTICE

If the truck is to be used or stored in an area with below freezing temperatures, the cooling system must be protected to the lowest expected ambient temperature. Never add coolant to an overheated engine; allow the engine to cool first. Do not use Caterpillar Cooling System Conditioner with Dowtherm 209 coolant.

1. Loosen the radiator cap slowly to release the pressure. Remove the radiator cap.

2. Remove the cooling system drain plug, and allow the coolant to drain.

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Use all cleaning solutions with care.

Most commercial cooling system cleaners may be used. The best cleaner is chelate type alkaline cleaners.

3. Install the drain plug. Fill the system with cleaning solution¹.

4. Start and run engine for 1/2 hour. Stop the engine and drain cleaning solution.

5. Flush the system with clean water until the draining water is clean. Do not run the engine while flushing.

6. Install the drain plug. Fill the system with neutralizing solution².

7. Start and run the engine for 10 minutes. Stop the engine and drain neutralizing solution.

8. Flush the system with clean water, until the draining water is clean. Do not run the engine while flushing.

9. Install the drain plug.

10. To help avoid air locks, add coolant slowly, at 5 U.S. gallons (19 liters) per minute or less.

11. Add antifreeze solution. See REFILL CAPACITIES.

12. Install the correct Cooling System Conditioner Precharge Element, or add the correct amount of Caterpillar Cooling System Conditioner, or equivalent, so that the cooling system will have a 3% concentration.

13. Start and run the engine with the radiator cap removed. Allow coolant to warm and level to stabilize.

14. Add coolant, if necessary, to bring the coolant level to the bottom of the fill pipe.

15. Observe condition of the radiator cap gasket. Replace if it is damaged.

¹2 lb. Sodium Bisulfate (NaHSO₄) per 10 gal. water (1 kg per 40 liters)

²1/2 lb. Sodium Carbonate Crystals (Na₂CO₃ · 10 H₂O) per 10 gal. (250 g per 40 liters)