Product Description
MAHLE 55523 is the Grade B multi-layer steel (MLS) cylinder head gasket for the 2017–2023 GM 6.6L Duramax L5P. It features a combustion load limiter and is designed for torque-to-yield fasteners. Thickness range: 1.19 mm–1.31 mm. Sold individually (use two for a complete engine).
- Engine: GM 6.6L Duramax L5P (VIN Y)
- Material: Multi-Layered Steel (MLS) with combustion load limiter
- Thickness: 1.19 mm–1.31 mm (Grade B)
- Fastener style: Torque-to-Yield (TTY)
- Qty required: 2 per engine (left/right banks)
Fitment
- 2017–2023 Chevrolet Silverado 2500/3500 HD – 6.6L Duramax L5P
- 2017–2023 GMC Sierra 2500/3500 HD – 6.6L Duramax L5P
Cross-Reference / Alternatives
- MAHLE Head Set (top end, without head gaskets): HS55522 – pair this with two 55523 gaskets for a complete top-end job.
- OE/Interchange numbers commonly referenced for L5P head gaskets: 12676859, 12727486 (verify grade before ordering).
- Related upgrades: ARP 230-4301 (ARP2000) or 230-4302 (Custom Age 625+) head stud kits for L5P.
FAQ
Is this the correct gasket for my 2017–2023 L5P?
Yes. MAHLE 55523 is listed for 2017–2023 GM 6.6L Duramax L5P engines. Always verify VIN and build details before install.
What does “Grade B” mean?
Grade B corresponds to a 1.19–1.31 mm thickness range to maintain proper compression after minor surfacing.
How many gaskets do I need?
Two—one per cylinder head/bank on the V-8 L5P.
Does this include head bolts or studs?
No. Use new TTY head bolts or upgrade to studs (e.g., ARP 230-4301/230-4302) during reassembly.
What other parts do I need to finish the job?
A top-end set (HS55522) covers valve cover, intake/exhaust and misc. seals not included with the individual head gasket.
