MAHLE 55524 Grade C Cylinder Head Gasket for 2017–2023 GM 6.6L Duramax L5P

Restore factory-level sealing performance and protect your engine with the MAHLE 55524 Grade C Multi-Layer Steel (MLS) Cylinder Head Gasket. Designed specifically for the 2017–2023 GM 6.6L Duramax L5P V8, this premium OE-quality gasket delivers reliable combustion chamber sealing under high cylinder pressures.

The Grade C gasket features a service thickness of approximately 1.30 mm (0.051") (range: 1.24–1.36 mm). It is the correct choice when cylinder heads or the engine block have undergone significant resurfacing and piston protrusion measurements call for the thickest available service gasket.

Sold individually — two gaskets required per engine (one per cylinder head/bank).

Key Features & Benefits

• Multi-Layer Steel (MLS) Construction — Provides exceptional strength, heat resistance, and long-term durability in high-output diesel applications.
• Grade C Thickness — Engineered for engines with higher piston protrusion (typically after head/block machining). Maintains proper quench height and compression ratio.
• OE-Quality Sealing — Meets or exceeds GM specifications for form, fit, and function on stock or lightly modified L5P engines.
• Torque-to-Yield (TTY) Compatible — Designed for one-time torquing to yield point for a secure, lasting seal.
• Precision Engineering — Features combustion load limiters and optimized sealing beads for excellent clamp-load retention through heat cycles.

Vehicle Fitment

• 2017–2023 Chevrolet Silverado 2500HD / 3500HD — 6.6L Duramax L5P
• 2017–2023 GMC Sierra 2500HD / 3500HD — 6.6L Duramax L5P

Note: Always verify piston protrusion measurements before ordering to select the correct grade (A, B, or C). Using the wrong thickness can lead to piston-to-head contact or incorrect compression.

Specifications

• Part Number: MAHLE 55524
• Material: Multi-Layer Steel (MLS)
• Grade: C
• Compressed Thickness: Approx. 1.30 mm (0.051") — Range: 1.24–1.36 mm
• Quantity: Sold individually (2 required per engine)
• Type: Direct-fit replacement

Important Installation Notes

• Measure piston protrusion at TDC on both banks and confirm the correct gasket grade.
• Use new torque-to-yield head bolts or quality aftermarket studs.
• Clean and inspect all sealing surfaces. Proper surface finish (RA/RZ) is critical for MLS gaskets.
• Follow GM/MAHLE torque procedures and sequences exactly.
• Head gaskets are one-time use components — always replace when removing cylinder heads.

Why Choose MAHLE?

MAHLE is a leading global manufacturer of engine components trusted by OEMs and diesel professionals. Their MLS head gaskets are engineered for consistent sealing, durability, and performance in demanding applications like towing, daily driving, and fleet service.

Perfect for: Head gasket replacement jobs on L5P Duramax engines where Grade C thickness is required due to machining or measured piston protrusion.