Cummins/Onan 6.5NH - 3CR / 6000 A — Cylinder Head Bolt Tightening
Repair & overhaul · Cylinder heads
For the Cummins/Onan 6.5NH - 3CR / 6000 A, from the Cummins/Onan service manual.
Applies to: Cummins/Onan NH engine
Procedure
- Tighten the cylinder head bolts in the designated order to the specified torque at room temperature.
- After the engine has been operated to normal hot temperature and allowed to cool to room temperature, retorque the head bolts.
- Retighten before the engine has been run a total of fifty hours.
- Beginning Spec C, cylinder head flat washers are also used with the cylinder head nuts.
Tools required
- Torque wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Cylinder head bolt 17-19 FridayParts $20.66 lb-ft
- Retorque after first 50 hours
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.