Cummins/Onan — Cylinder Head Removal and Installation
Maintenance · Cylinder heads
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan NHP / NHPV engine
Before you start
- Do not remove heads when they are hot. Warpage may occur.
Procedure
- Use a 9/16-inch socket wrench to remove cylinder head bolts; lift heads off.
- After removing heads, clean out all carbon deposits carefully.
- Use new head gaskets and clean heads and cylinder block thoroughly.
- Place heads in position and tighten bolts in sequence to 5 ft-lb, then 10 ft-lb, etc.
- Torque all bolts to 15 ft-lb (20 N.m).
- Recheck torque before engine has run a total of 50 hours.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 15 ft-lb (20 N.m)
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.