Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2003 Hummer H2 V8-6.0LFACTORY OEM SERVICE PROCEDURE
Piston Ring, Engine
Piston Ring End Gap - First Compression Ring - Measured in Cylinder Bore - Production 0.31-0.52 mm (0.012-0.02 in)
Piston Ring End Gap - First Compression Ring - Measured in Cylinder Bore - Service 0.31-0.59 mm (0.0122-0.023 in)
Piston Ring End Gap - Second Compression Ring - Measured in Cylinder Bore - Production 0.51-0.77 mm (0.02-0.03 in)
Piston Ring End Gap - Second Compression Ring - Measured in Cylinder Bore - Service 0.51-0.84 mm (0.02-0.033 in)
Piston Ring End Gap - Oil Control Ring - Measured in Cylinder Bore - Production 0.31-0.87 mm (0.0122-0.034 in)
Piston Ring End Gap - Oil Control Ring - Measured in Cylinder Bore - Service 0.31-0.94 mm (0.0122-0.037 in)
Piston Ring to Groove Clearance - First Compression Ring - Production 0.04-0.08 mm (0.00157-0.0031 in)
Piston Ring to Groove Clearance - First Compression Ring - Service 0.04-0.08 mm (0.00157-0.0031 in)
Piston Ring to Groove Clearance - Second Compression Ring - Production 0.039-0.079 mm (0.0015-0.0031 in)
Piston Ring to Groove Clearance - Second Compression Ring - Service 0.039-0.079 mm (0.0015-0.0031 in)
Piston Ring to Groove Clearance - Oil Control Ring - Production 0.015-0.199 mm (0.0006-0.0078 in)
Piston Ring to Groove Clearance - Oil Control Ring - Service 0.015-0.199 mm (0.0006-0.0078 in)
Piston Ring End Gap - First Compression Ring - Measured in Cylinder Bore - Service 0.31-0.59 mm (0.0122-0.023 in)
Piston Ring End Gap - Second Compression Ring - Measured in Cylinder Bore - Production 0.51-0.77 mm (0.02-0.03 in)
Piston Ring End Gap - Second Compression Ring - Measured in Cylinder Bore - Service 0.51-0.84 mm (0.02-0.033 in)
Piston Ring End Gap - Oil Control Ring - Measured in Cylinder Bore - Production 0.31-0.87 mm (0.0122-0.034 in)
Piston Ring End Gap - Oil Control Ring - Measured in Cylinder Bore - Service 0.31-0.94 mm (0.0122-0.037 in)
Piston Ring to Groove Clearance - First Compression Ring - Production 0.04-0.08 mm (0.00157-0.0031 in)
Piston Ring to Groove Clearance - First Compression Ring - Service 0.04-0.08 mm (0.00157-0.0031 in)
Piston Ring to Groove Clearance - Second Compression Ring - Production 0.039-0.079 mm (0.0015-0.0031 in)
Piston Ring to Groove Clearance - Second Compression Ring - Service 0.039-0.079 mm (0.0015-0.0031 in)
Piston Ring to Groove Clearance - Oil Control Ring - Production 0.015-0.199 mm (0.0006-0.0078 in)
Piston Ring to Groove Clearance - Oil Control Ring - Service 0.015-0.199 mm (0.0006-0.0078 in)
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.