Caterpillar 3412 DITA Engine

⚠ Replace belts for multiple groove pulleys in matched sets.

Tools: Belt tension gauge (110 N / 25 lb force)

1. Remove the belt guard.
2. Loosen mounting bolt (2) and adjusting nuts (1).
3. Turn adjusting nuts to increase or decrease belt tension.
4. Check deflection is 13 to 19 mm with 110 N applied midway.
5. Tighten the adjusting nuts; tighten the mounting bolt.
6. Reinstall the belt guard.
7. Check adjustment again after 30 minutes at rated rpm if new belts.

1. Warm Up
2. Start
3. 15 Min
4. 30 Min
5. 45 Min
6. 1 Hour
7. Cool Down

⚠ Do not use a high concentration of caustic cleaner to clean the core.

⚠ Maximum air pressure at the nozzle must be less than 205 kPa (30 psi).

Tools: Pressure air supply (maximum 205 kPa / 30 psi at nozzle)

1. Remove the core. Refer to the Service Manual for the procedure.
2. Turn the aftercooler core upside-down in order to remove debris.
3. Back flush the core with cleaner (1U-5490 or 174-6854 Hydrosolv).
4. Steam clean the core to remove residue; flush the fins.
5. Wash the core with hot, soapy water; rinse thoroughly with clean water.
6. Dry the core with compressed air in the reverse direction of normal flow.
7. Inspect the core for cleanliness; pressure test; repair if necessary.
8. Install the core. Refer to the Service Manual for the procedure.

1. Verify proper operation of exerciser clock; adjust if necessary.
2. Provide visual inspection of all contacts and connection points.
3. Perform building load test if practical and inspect for proper transfer and re-transfer.
4. Verify operation of all control lamps.

⚠ All lead-acid batteries contain sulfuric acid; wear face shield and protective clothing.

Tools: 245-5829 Coolant Battery Tester Refractometer

1. Remove the filler caps; maintain the electrolyte to the FULL mark.
2. Add distilled water if necessary; avoid artificially softened water.
3. Check electrolyte condition with the 245-5829 Coolant Battery Tester Refractometer.
4. Clean battery case with baking soda/water or ammonia/water solution; rinse.
5. Clean terminals and cable clamps with fine grade sandpaper.
6. Coat clamps and terminals with 5N-5561 Silicone Lubricant, petroleum jelly or MPGM.
7. Clean the battery case; keep the batteries clean.

1. Clean all battery terminals; verify integrity of cables and connectors.
2. Load-test battery.
3. Measure specific gravity of each battery cell.
4. Inspect electrolyte level and add fluid if necessary.
5. Verify proper operation and float voltage of external battery charger.
6. Verify and record output of engine alternator.

1. Verify and record output voltage and adjust voltage regulator, if necessary.
2. Calibrate control meters.
3. Verify and record output frequency and adjust governor, if necessary.
4. Verify operation of all control panel lamps.
5. Inspect for any loose connections, terminals or discoloration.

1. Inspect all clamps, verify condition of all hoses and identify any leaks.
2. Verify proper operation of engine water jacket heater.
3. Test coolant freeze point and verify coolant level.
4. Test coolant additive package for proper corrosion inhibitors.
5. Inspect belt condition and tension; correct as required.
6. Inspect radiator core for visual blockage or obstructions.
7. Inspect for proper operation of intake louvers.
8. Verify proper operation of remote radiator and belt condition.

⚠ Pressurized System: Hot coolant can cause serious burns.

⚠ Stop the engine and wait until cooling system components are cool.

Tools: 9S-8140 Pressurized Pump Group (filler cap pressure test)

1. Observe coolant level in recovery tank; maintain to COLD FULL mark.
2. Loosen filler cap slowly to relieve pressure; remove the filler cap.
3. Pour proper coolant mixture into tank; do not fill above COLD FULL.
4. Clean filler cap and receptacle; reinstall; inspect system for leaks.
5. Without a recovery tank, maintain level within 13 mm of filler pipe bottom.
6. Clean and inspect filler cap gaskets; replace damaged cap.

1. Visual inspection of Radiator/Heat exchanger for leaks, damage and obstructions.
2. Add coolant to correct level.
3. Inspect radiator cap, gasket and sealing surface.
4. Visual inspection of water pump and cooling system gaskets for leaks.
5. Inspect belts for cracking and fraying.
6. Check water jacket heater for proper operation and adjust thermostat setting as needed.
7. Check belt tension.
8. Inspect flexible water connections for cracking, leaks and pliability.
9. Inspect pulleys for excessive wear.
10. Analyze coolant for proper antifreeze percentage.
11. Analyze coolant conditioner level and add supplemental coolant additive as needed.
12. Tighten hose clamps as needed.
13. Lubricate fan drive with bearing lubricant.

⚠ Perform this maintenance with the engine stopped.

⚠ A plugged crankcase breather will cause excessive crankcase pressure.

1. Loosen hose clamp (1) and remove the hose from breather assembly (2).
2. Loosen retaining clamp (3); remove the breather assembly and seal (4).
3. Wash the breather element in clean, nonflammable solvent.
4. Allow the breather element to dry before installation.
5. Install a clean, dry element, the seal, the breather assembly, and the clamp.
6. Install the hose and the hose clamp; refer to SENR3130 for torques.

⚠ Hot oil and hot components can cause personal injury.

⚠ Do not fill the oil filters with oil before installing them.

⚠ Do not crank the engine for more than 30 seconds.

Tools: 1U-8760 Chain Wrench, 175-7546 Oil Filter Cutter Gp

1. Run the engine at normal operating temperature, then stop the engine.
2. Drain the crankcase through the drain valve or the oil drain plugs.
3. Remove the oil filter with a 1U-8760 Chain Wrench.
4. Cut the filter open with a 175-7546 Oil Filter Cutter Gp; inspect for debris.
5. Clean the filter mounting base sealing surface; remove all old gasket.
6. Apply clean engine oil to new filter gasket; install filter hand tight.
7. Fill crankcase between the ADD mark and the FULL mark on the gauge.
8. Run engine at low idle two minutes; inspect filter for leaks; check level.