Product Description
MAHLE 55523 (Grade B) multi-layer steel (MLS) cylinder head gasket restores factory-tight combustion sealing on 2017–2023 Chevy/GMC 6.6L Duramax L5P (VIN Y). Designed with a combustion load limiter for high cylinder pressures, this OE-grade MLS gasket works with torque-to-yield fasteners to maintain clamp load in towing, work, and performance daily-driver builds.
Fitment
- 2017–2023 Chevrolet Silverado 2500HD/3500HD – 6.6L Duramax L5P (VIN Y)
- 2017–2023 GMC Sierra 2500HD/3500HD – 6.6L Duramax L5P (VIN Y)
- Quantity: Sold individually. Order two gaskets (one per bank) for a complete engine.
Cross-Reference / Mahle Alternatives (working internal links)
- MAHLE 55522 – Grade A L5P MLS Head Gasket
- MAHLE 55524 – Grade C L5P MLS Head Gasket
- MAHLE VS50966 – L5P Valve Cover Gasket Set
Why MAHLE
- OE-grade MLS construction with combustion load limiter
- Stable clamp load with TTY fasteners; proven sealing under heavy load
- Direct fit for L5P—no guesswork on ports or fire-ring geometry
Install Notes
- Measure piston protrusion and surface finish; select Grade A/B/C accordingly
- Always use new TTY bolts or head studs; follow GM/MAHLE torque sequence
- Clean, flat deck and head surfaces are critical for MLS sealing
FAQ
What does “Grade B” mean on L5P head gaskets?
Grade B corresponds to an L5P service thickness in the ~1.19–1.31 mm range, commonly used after minor surfacing. Verify against your measured piston protrusion.
How many 55523 gaskets do I need?
Two—one per cylinder head/bank on the V-8 L5P.
Does this include bolts or studs?
No. Use new TTY bolts or quality head studs during reassembly.
Specifications for Mahle 55523
| Attribute | Value |
|---|---|
| Brand | MAHLE / Clevite |
| Part Number | 55523 (Grade B) |
| Engine Compatibility | 2017–2023 GM 6.6L Duramax L5P (VIN Y) |
| Material | Multi-Layer Steel (MLS) with combustion load limiter |
| Thickness (service, Grade B) | ~1.19–1.31 mm |
| UPC (GTIN-12) | 639789320216 |
| GTIN | 00639789320216 |
| Shipping Info | Ships from CPP Diesel; shipping calculated at checkout (optional shipping insurance available). Package dims listed on page. |
| Prop 65 | Not listed as a Prop 65 item by several distributors. Always consult P65Warnings.ca.gov for general info. |
