D346, D348 & D349 VEHICULAR ENGINES Caterpillar

When Required

Usage:

(13)Fuel System-Clean Primary Fuel Filter:

1. Stop the engine and shut off the fuel supply valve from the fuel tank.

2. Loosen the retaining nut (1) on the filter cover.

3. Lower the filter case (3) and element (4).

4. Remove the filter element from the case. Clean the element and case in nonflammable solvent.

5. Reinstall the element in the case.

6. Inspect the seal (2). Use a new seal if the used one is damaged.

7. Install the element and case on the housing. Install the retaining nut.

8. Open the fuel supply valve.

Final Fuel Filters-D346

1. Close the fuel supply line valve.

2. Use a strap wrench to remove the fuel filters.

3. Clean the filter base. Be sure to remove all of the old gasket. Apply a light coat of clean fuel to the new filter gasket.

4. Install the new filter by hand. When the seal contacts the base, tighten 3/4 turn more. Use the rotation index marks on the filter as a guide for proper tightening.

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NOTICE

Do not overtighten the filter.

5. Open the fuel supply valve and prime the system.

6. Start the engine and inspect for leaks.

Final Fuel Filters-D348 and D349

1. Close the fuel supply valve.

2. Open the "FILTER BLEED" valve (A).

3. Turn the drain valve rod (B) to drain the filter housing.

4. Remove the cover and the filter elements.

5. Remove the old elements. Replace them with new elements.

6. Install a new filter cover gasket.

7. Install the cover and the elements.

8. Close the filter housing drain valve.

9. Open the fuel supply line valve.

10. Prime the fuel system.

11. Start the engine and inspect for leaks.

Priming The Fuel System-D346

1. Open the rear vent valve.

2. Unlock the priming pump plunger.

3. Operate the pump until the fuel flows from the drain tube free of air bubbles.

4. If it is necessary to prime the fuel injection pump housing, open the front bleed valve, designated "INJ PUMP BLEED", and operate the priming pump until the fuel flows free of bubbles.

5. Close the vent valve(s) and lock the pump.

6. Start the engine. If the engine misfires, loosen the individual fuel injection line nuts, one at a time, until the fuel flows free of air bubbles or the misfiring is eliminated.

Priming The Fuel System-D348 and D349

1. Open the rear vent valve.

2. Unlock the priming pump plunger.

3. Operate the pump until the fuel flows free of air bubbles from the drain tube.

4. If it is necessary to prime the injection pump housing, open the front vent valve. Operate the pump until the fuel flows free of air bubbles.

5. Close the vent valve(s) and lock the pump.

6. Start the engine. If the engine misfires, loosen the individual fuel injection line nuts, one at a time, until the fuel flows free of air bubbles or the misfiring is eliminated

(14)Cooling System-Cleaning

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

Inhibitor contains alkali. Avoid contact with skin and eyes to prevent personal injury.

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NOTICE

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

1. Loosen radiator cap slowly to release pressure, and remove filler cap.

2. Remove the radiator drain plug(s).

3. Remove the engine block drain plugs.

4. Remove the thermostat housing drain plugs.

5. Remove the oil cooler bonnet drain plug.

Draining Aftercooler Cooling System

Remove the drain plug from the auxiliary aftercooler water pump.

Remove the aftercooler pipe drain plug.

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Use all cleaning solutions with care.

Most commercial cooling system cleaners may be used.

6. Install all drain plugs. Fill the system(s) with cleaning solution. ⁽¹⁾

7. Start and run engine for 1/2 hour. Stop engine and drain the cleaning solutions(s).

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

9. Install all drain plugs. Fill the system(s) with neutralizing solution. ⁽²⁾

10. Start and run engine for 10 minutes. Stop engine and drain the neutralizing solution(s).

11. Flush the system(s), with clean water, until draining water is clean. Do not run engine while flushing.

12. Install all drain plugs.

13. Mix antifreeze solution to provide protection to the lowest expected ambient temperature.

14. Add the correct amount of Caterpillar Corrosion Inhibitor, or equivalent, so that this cooling system will have a 3% concentration of inhibitor.

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

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

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

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

⁽¹⁾2 lb. Sodium Bisulfate (NaHSO₄) per 10 U.S. gallons (1 kilogram per 10 liters) water.

⁽²⁾1/2 lb. Sodium Carbonate Crystals (Na₂CO₃* 10 H₂O) per 10 U.S. gallons (250 grams per 40 liters) water.

(15)Glow Plugs-Testing Glow Plugs

1. Stop the engine.

2. Disconnect the lead harness wire from the magnetic switch.

3. Connect an ammeter of over 75 amps capacity between the magnetic switch terminal and the lead harness wire.

4. Push in, turn and hold the HEAT-START switch in the HEAT position. Each glow plug draws approximately 5 amps.

5. The ammeter reading should be approximately equal to the number of glow plugs multiplied by 5. A reading of 5 or more amps less than this, usually indicates one or more of the glow plugs is defective.

6. Release the HEAT-START switch.