Torque Spec For Flywheel | Bolts On Isx Cummins 251 Updated =link=

Cummins ISX

Ensuring the correct torque for flywheel bolts on a (including ISX15 and X15 models) is critical to preventing engine vibration, crankshaft damage, and potential catastrophic failure. Based on the latest updated service guidelines for 2026, the standard torque procedure follows a multi-step sequence to ensure even clamping force. Cummins ISX Flywheel Bolt Torque Specifications

• Flywheel Bolt Torque: 70-80 ft-lb (95-108 Nm) in a star pattern

ISX engines with the updated 14-bolt flywheel pattern

For (typically engines after 2010 with the deep-skirt block, casting # 4940639 or 5350251): torque spec for flywheel bolts on isx cummins 251 updated

Important Note on "251 Updated":

The reference to "251" typically relates to the ISX 15 CM2250 and later models (CM2350/X15) which utilize a Dual Mass Flywheel (DMF) . The torque specs changed significantly from the older solid flywheels to these newer dual-mass units. Cummins ISX Ensuring the correct torque for flywheel

Conclusion

The term “251” refers to the SAE housing size (SAE #1) but specifically the flywheel mounting pattern. The ISX uses a heavy dual-mass or solid flywheel with a specific bolt circle. The 251mm housing is standard on most over-the-road ISX engines (Peterbilt, Kenworth, Freightliner). Getting the flywheel torque wrong is dangerous, but confusing it with the flexplate torque (used in motorhomes or industrial pumps) is catastrophic. Flywheel Bolt Torque: 70-80 ft-lb (95-108 Nm) in

Cummins ISX (251 Update)

Here is the definitive, updated torque specification for flywheel bolts on the .

Importance of Correct Torque Specifications