Cummins/Onan K38 Generator Set

⚠ Over-tensioning of alternator belts can result in premature accessory drive bushing wear and seal leakage.

Tools: GT-1293 Burroughs Tension Gauge

1. Loosen the alternator and adjusting link mounting capscrews.
2. Loosen the jam nuts on the adjusting screw.
3. Turn the adjusting screw clockwise to tighten the belt tension.
4. Check the belt tension with a gauge.
5. Tighten the jam nuts on the adjusting screw to 55 Nm [40 ft-lb].
6. Tighten the adjusting link and alternator mounting capscrews to 55 Nm [40 ft-lb].
7. Check the belt tension again.

Tools: ST-669 Torque Wrench Adapter

1. Adjust the crossheads on the cylinder that has both valves closed.
2. Loosen the crosshead adjusting screw locknuts on the intake and exhaust valve crossheads.
3. Turn the adjusting screw out at least one turn.
4. Hold the crosshead down against its guide.
5. Turn the adjusting screw in until it touches the top of the valve stem but does not raise the crosshead.
6. Hold the adjusting screw and tighten the lock nut to the torque value.

⚠ The dipstick will break if the scribe mark is too deep.

Tools: scribe

1. Drain the oil from the pan.
2. Install the dipstick in the dipstick tube.
3. Use clean 15W-40 oil to fill the oil pan to the specified low level.
4. Remove the dipstick and scribe a mark across the dipstick at the oil level. Mark the low level with an L.
5. Install the dipstick and add additional oil to the specified full level.
6. Remove the dipstick and scribe a mark across the dipstick at the oil level. Mark the high oil level with an H.

⚠ The injector plunger is under spring tension. Do NOT allow the tool to slip.

Tools: 3822575 adjustment kit, 3822574 rocker lever actuator, ST-669 adapter

1. Install injector and valve adjustment kit, Part No. 3822575.
2. Adjust indicator tip to touch top of injector plunger.
3. Lower indicator 12.25 mm [0.5 inch] and lock support.
4. Depress rocker lever until injector bottoms two or three times.
5. Hold plunger bottomed and set indicator to ZERO.
6. Turn adjusting screw until indicator reads specified travel.
7. Tighten locknut; verify setting.

⚠ Use the correct chart for the engine being serviced or the parts will be damaged.

Tools: 3376592 Inch Pound Torque Wrench, ST-669 Torque Wrench Adapter, feeler gauge

1. Select a feeler gauge for the correct valve lash specification and insert the gauge between the rocker lever and the crosshead.
2. Torque wrench method: use Part No. 3376592 inch pound torque wrench and tighten the adjusting screw to 0.68 Nm [6 in-lb].
3. Feel method: use a screwdriver and turn the adjusting screw only until the lever touches the feeler gauge.
4. The adjusting screw must not turn when the locknut is tightened.
5. Tighten the locknut to the value indicated.
6. The feeler gauge must slide backward and forward with only a slight drag.
7. Attempt to insert a feeler gauge 0.03 mm [0.001 in] thicker; the lash is not correct when the thicker gauge will fit.
8. Repeat until clearance is correct on both intake and exhaust valves.

⚠ Use the correct chart for the engine or the parts will be damaged.

⚠ Crosshead adjustment must always be made before adjusting the valves.

Tools: 3376592 inch pound torque wrench, 3822575 injector and valve adjustment kit, 3822574 rocker lever actuator, ST-669 torque wrench adapter

1. Steam clean engine before removing rocker lever covers.
2. Remove rocker lever covers and related components.
3. Align valve set (VS) mark on damper or flywheel with pointer.
4. Determine cylinder in position; crossheads and valves ready when all valves closed.
5. Adjust crossheads before adjusting valves.
6. Adjust valves to lash specification with feeler gauge.
7. Adjust injectors per PT (type D) or STC/HVT method.
8. Tighten locknuts and reinstall rocker lever covers.

⚠ Holes, loose end seals, dented sealing surfaces and other damage require immediate element replacement.

⚠ Pull the cover and element straight out to avoid damage.

1. Wipe dirt from the cover and upper portion of the air cleaner before disassembly.
2. Loosen the wing bolt and band clamp securing the dust pan.
3. Loosen the wing nut and remove the dust shield from the dust pan. Clean the dust pan and shield.
4. Remove the wing nut securing the primary element and inspect the rubber sealing washer.
5. Remove the dirty cleaner element and install the new primary element.
6. Make sure the rubber sealing washer is in place under the wing nut before tightening.
7. Assemble the dust shield and dust pan and secure with the band clamp.

⚠ Do NOT remove the radiator cap from a hot engine.

⚠ Do not allow oil to get in the filter; it will adversely affect the DCA.

1. Remove the coolant system pressure cap and close the shutoff valve(s), if equipped, before removing the coolant filter.
2. Push in the knob on the filter head or close the gate valve.
3. Lubricate the seal on the new filter with engine oil.
4. Install the new coolant filter. Turn the filter until the seal touches the filter head.
5. Turn the filter an additional 1/2 to 3/4 of a turn after contact.
6. Pull the knob on the filter head out or open the gate valve.

⚠ Do not use caustic cleaners; aluminum components will be damaged.

⚠ Wait until temperature is below 50 C [120 F] before removing the pressure cap.

1. Drain the cooling system; do not allow it to dry out.
2. Add Fleetguard RESTORE or RESTORE PLUS (1 U.S. gallon per 38-57 liters capacity).
3. Fill system with plain water.
4. Operate engine at normal temperature (at least 85 C [185 F]) for 1 to 1.5 hours.
5. Shut off and drain the system.
6. Fill with clean water and operate at high idle 5 minutes above 85 C.
7. Shut off and drain; repeat flush if water is still dirty.
8. Refill with new heavy duty coolant and SCA.

⚠ Do not use caustic cleaners in the cooling system. Aluminum components will be damaged.

⚠ Wait until the temperature is below 50 C [120 F] before removing the coolant system pressure cap.

1. Drain the cooling system. Do not allow the cooling system to dry out. Do not remove the coolant filter.
2. Add 3.8 liters [1 U.S. gallon] of Fleetguard RESTORE (or equivalent) for each 38 to 57 liters [10 to 15 gallons] of cooling system capacity and fill with plain water.
3. Turn the heater temperature switch to high to allow maximum coolant flow.
4. Operate the engine at normal operating temperatures (at least 85 C [185 F]) for 1 to 1 1/2 hours.
5. Shut the engine off and drain the cooling system.
6. Fill with clean water to flush and operate at high idle for 5 minutes above 85 C [185 F].
7. Shut the engine off and drain. Repeat flushing if the water is still dirty.
8. Refill the system with new heavy duty coolant and SCA.

⚠ The fan belt idler is under tension. Do NOT allow your hands between the idler and belt or fan hub.

Tools: 8-point socket, breaker bar

1. Remove the back side idler end of the shock absorber, control rod, or turnbuckle.
2. Loosen upper capscrew and remove lower capscrew.
3. Relieve idler spring tension with an 8-point socket and breaker bar.
4. Remove the fan belt.
5. Install the belt on crankshaft and fan hub pulley, aligning grooves with pulley ribs.
6. Rotate idler against spring and install lock washer and capscrew; torque 45 Nm.
7. Install control rod or shock absorber and tighten capscrews to 60-90 Nm.

Tools: dial indicator

1. Remove the fan belt.
2. Rotate the fan hub pulley to check for rough or damaged bearings.
3. Inspect the pulley grooves for excessive wear.
4. Check for grease leakage.
5. Use a dial indicator to check the bearing end clearance.
6. Replace with a new or rebuilt unit as necessary.
7. Install the fan belt.