Caterpillar 3126B Generator Set

⚠ Replace belts that are worn or damaged. Replace multiple drive belts in matched sets.

1. Check belt tension initially between the first 20 to 40 hours of engine operation, with the engine stopped.
2. Apply 110 N (25 lb ft) of force midway between the pulleys; a correctly adjusted belt will deflect 9 mm (0.35 inch) to 15 mm (0.59 inch).
3. For alternator belt: slightly loosen mounting bolts and adjusting bolt, move pulley to adjust tension, then tighten.
4. For water pump belt: slightly loosen mounting bolt and adjusting bolt, adjust tension with a square drive in square hole, then tighten.
5. Install the belt guard.
6. If new belts are installed, check tension again after 30 minutes of operation at rated rpm.

⚠ Only qualified service personnel should perform this maintenance.

⚠ Do not use the starting motor to turn the flywheel.

⚠ Hot engine components can cause burns.

1. Ensure that the engine can not be started while this maintenance is being performed.
2. Allow the engine to cool before measuring/adjusting valve lash clearance.
3. Ensure the engine is stopped before measuring the valve lash.
4. Refer to the Service Manual for the complete valve lash adjustment procedure.

1. Turn cruise control switch to OFF position.
2. Move SET/RESUME switch to either position and hold.
3. Record two-digit flash codes: short pause between digits, long pause between codes.
4. Refer to Engine Diagnostics table in the O & M manual and consult your local Caterpillar dealer.

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

⚠ Personal injury can result from air pressure.

1. Remove the core. Refer to the Service Manual.
2. Turn the aftercooler core upside-down in order to remove debris.
3. Back flush the core with cleaner. Caterpillar recommends Hydrosolv liquid cleaner.
4. Steam clean the core to remove any residue. Flush the fins. Remove any other trapped debris.
5. Wash the core with hot, soapy water. Rinse thoroughly with clean water.
6. Dry the core with compressed air, directing the air in reverse of normal flow.
7. Inspect the core for cleanliness. Pressure test the core. Repair if necessary.
8. Install the core. Refer to the Service Manual.

⚠ Batteries give off combustible gases which can explode.

⚠ The battery cover should be removed before any servicing is attempted.

1. Turn the key start switch to the OFF position. Remove the key and all electrical loads.
2. Turn OFF the battery charger. Disconnect the charger.
3. Disconnect the NEGATIVE "-" cable from the NEGATIVE "-" battery terminal.
4. Disconnect the POSITIVE "+" cable from the POSITIVE "+" battery terminal.
5. Remove the used battery.
6. Install the new battery.
7. Connect the cable from the starting motor to the POSITIVE "+" battery terminal.
8. Connect the cable from the ground plane to the NEGATIVE "-" battery terminal.

⚠ All lead-acid batteries contain sulfuric acid which can burn the skin and clothing. Always wear a face shield and protective clothing.

Tools: 1U-7298 Coolant/Battery Tester (°C), 1U-7297 Coolant/Battery Tester (°F)

1. Remove the filler caps. Maintain the electrolyte level to the "FULL" mark on the battery.
2. Add distilled water if necessary; do not use artificially softened water.
3. Check the condition of the electrolyte with the 1U-7298 or 1U-7297 Coolant/Battery Tester.
4. Keep the batteries clean.
5. Clean the battery case with a baking soda/water or ammonia/water solution and rinse.
6. Clean the terminals and cable clamps; coat with 5N-5561 Silicone Lubricant, petroleum jelly or MPGM grease.

⚠ Do not leave an empty SCA filter on an ELC system.

⚠ Improper or incomplete rinsing of the cooling system can result in damage to copper and other metal components.

1. Drain the coolant into a suitable container.
2. Dispose of the coolant according to local regulations.
3. Remove the empty SCA filter and remove the filter base. Plug the coolant lines or bypass the coolant lines.
4. Flush the system with clean water in order to remove any debris.
5. Use Caterpillar cleaner to clean the system. Follow the instruction on the label.
6. Drain the cleaner into a suitable container. Flush the cooling system with clean water.
7. Fill the cooling system with clean water and operate the engine until warmed to 49° to 66°C (120° to 150°F).
8. Drain the cooling system and flush with clean water.
9. Repeat the fill/flush steps until the system is completely clean.
10. Fill the cooling system with the Caterpillar premixed ELC.
11. Attach the Label (PEEP5027) to the cooling system filler to indicate use of Caterpillar ELC.

⚠ Do not tap or strike the filter element.

⚠ Do not wash the filter element.

Tools: 60 watt blue light

1. Visually inspect the primary element before cleaning; discard damaged elements.
2. Pressurized air: use filtered, dry air with a maximum pressure of 207 kPa (30 psi); begin with the clean side (inside).
3. Aim the hose so air flows inside the element along the length of the filter.
4. Vacuum cleaning: recommended prior to vacuum cleaning; will not remove carbon and oil deposits.
5. Inspect the clean, dry element with a 60 watt blue light in a dark room for tears or holes.
6. Discard any element that has tears, holes, or damaged pleats, gaskets or seals.
7. Store unused elements wrapped in Volatile Corrosion Inhibited (VCI) paper in a dry location.

⚠ Pressurized System: Hot coolant can cause serious burns.

⚠ Never add coolant to an overheated engine.

Tools: 9S-8140 Pressurizing Pump

1. Stop the engine and allow the engine to cool. Loosen the filler cap slowly to relieve pressure. Remove the filler cap.
2. Open the cooling system drain valve (or remove a drain plug). Allow the coolant to drain.
3. Flush the cooling system with clean water to remove debris.
4. Close the drain valve; clean and install the drain plugs.
5. Fill with clean water and Caterpillar Fast Acting Cooling System Cleaner (0.5 L per 15 L capacity). Install filler cap.
6. Start and run the engine at low idle for a minimum of 30 minutes; coolant temperature at least 82 °C (180 °F).
7. Stop engine, cool, drain and flush with clean water. Close drain and install drain plugs.
8. Fill the cooling system with coolant/antifreeze. Do not install the filler cap.
9. Start and run engine at low idle; increase to 1500 rpm; run at high idle one minute to purge air. Stop engine.
10. Check coolant level to within 13 mm (0.5 inch) below the bottom of the filler pipe.
11. Clean and inspect the filler cap gasket. Pressure test the cap with a 9S-8140 Pressurizing Pump.
12. Start the engine. Inspect the cooling system for leaks and proper operating temperature.

⚠ Pressurized System: Hot coolant can cause serious burns.

Tools: 9S-8140 Pressurizing Pump

1. Stop the engine and allow the engine to cool. Loosen the filler cap slowly to relieve pressure. Remove the filler cap.
2. Open the drain valve (or remove drain plugs) and allow the coolant to drain.
3. Flush the cooling system with clean water to remove debris.
4. Close the drain valve; clean and install the drain plugs.
5. Fill with clean water. Install the filler cap.
6. Start and run the engine at low idle until temperature reaches 49 to 66 °C (120 to 150 °F).
7. Stop engine, cool, drain and flush with clean water. Close drain and install drain plugs.
8. Fill the cooling system with Extended Life Coolant (ELC). Do not install the filler cap.
9. Start and run engine at low idle; increase to high idle; run one minute to purge air. Stop engine.
10. Check coolant level to within 13 mm (0.5 inch) below the bottom of the filler pipe.
11. Clean and inspect the filler cap gasket; pressure test with a 9S-8140 Pressurizing Pump.
12. Start the engine. Inspect the cooling system for leaks and proper operating temperature.

⚠ DO NOT use commercial antifreeze with high silicate content formulated for gasoline engines.

1. Use only distilled or deionized water.
2. Antifreeze must be a low silicate type that meets TMC RP329, ASTM D5345, or D4985 specifications. DO NOT use commercial antifreeze with high silicate content formulated for gasoline engines.
3. Use conditioner or inhibitor to maintain a three to six percent concentration in cooling system. Requirements are different for ELC (Extended Life Coolant) — consult your dealer.
4. Do not mix different antifreeze and conditioners.
5. Cat ELC recommended for six-year protection. Meets Cat EC-1 specification.

⚠ Never run the engine without an air cleaner element installed.

⚠ Never service the air cleaner element with the engine running.

1. Remove the cover. Remove the primary air cleaner element.
2. Remove and discard the secondary element for every three cleanings of the primary element.
3. Cover the turbocharger air inlet with tape to keep dirt out.
4. Clean the inside of the air cleaner cover and body with a clean, dry cloth.
5. Remove the tape. Install the secondary air cleaner element. Install a new or cleaned primary element.
6. Install the air cleaner cover.
7. Reset the air cleaner service indicator.