Cummins/Onan 5.6TGHAA11381C — Valve Clearance (Lash) Adjustment
Adjustments · Valve system
For the Cummins/Onan 5.6TGHAA11381C, from the Cummins/Onan service manual.
Applies to: Cummins/Onan TGHAA
Procedure
- Adjust the valve clearance only when the engine is at ambient temperature.
- Remove all parts that block access to the valve tappets.
- Remove the spark plugs to make turning the engine easier.
- Use a 3/8 inch allen wrench in the rotor through bolt to rotate the crankshaft counterclockwise until the right intake valve opens and closes.
- Continue turning until the TC mark on the flywheel lines up with the TC mark on the gear cover (right piston at top of compression stroke).
- Verify the right intake and exhaust valves are closed and there is no pressure on the valve lifters.
- Measure clearance; the feeler gauge should just pass between the valve stem and valve tappet.
- Turn the self-locking adjusting screw as needed to correct the clearance.
- Turn the engine one complete revolution to align the TC marks and repeat for the left cylinder.
- Replace all parts removed.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Intake valve clearance (cold) 0.005 inch (0.13 mm)
- Exhaust valve clearance (cold) 0.013 inch (0.33 mm)
Full service-parts list: Cummins/Onan TGHAA →
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.