Product Description
MAHLE 54585 is the LEFT/driver-side Grade C (1.05 mm) MLS head gasket for the 2001–2016 GM 6.6L Duramax. Built from multi-layer steel for high cylinder pressures, it’s an OE-grade replacement that restores sealing integrity on LB7, LLY, LBZ, LMM, and LML engines. Head bolts/studs not included.
- Position: Left (Driver Side)
- Thickness: 1.05 mm (Grade C)
- Bore: 105.4 mm
- Material: Multi-Layer Steel (MLS)
- Standard bore application; use with properly finished head/block surfaces
Fitment
- 2001–2004 LB7 6.6L Duramax – Silverado/Sierra 2500HD/3500HD
- 2004.5–2005 LLY 6.6L Duramax – Silverado/Sierra 2500HD/3500HD
- 2006–2007 LBZ 6.6L Duramax – Silverado/Sierra 2500HD/3500HD
- 2007.5–2010 LMM 6.6L Duramax – Silverado/Sierra 2500HD/3500HD
- 2011–2016 LML 6.6L Duramax – Silverado/Sierra 2500HD/3500HD
- Also used on certain 6.6L Express/Savana vans (left/Grade C).*
*Verify by VIN/RPO and side before ordering.
Cross Reference Numbers
- GM: 12637785 (Left, Grade C, 1.05 mm)
- Superseded/related GM #s: 19301790, 97188469, 97288228, 97309564, 97333727, 97378104, 97389258, 98030633, 98045060, 98062785
- GTIN/UPC: 027067719935
What’s Included
(1) Left-side head gasket (Grade C, 1.05 mm). Head bolts or studs sold separately.
Installation Notes
- Check flatness and RA; MLS gaskets require correct surface finish.
- Replace torque-to-yield head bolts, or upgrade to studs during reassembly.
- Confirm left vs. right gasket before opening packaging.
FAQ
Is this the correct thickness?
Yes—Grade C is 1.05 mm, commonly used on stock rebuilds when piston protrusion is within spec.
Which side does 54585 fit?
Left/driver side. The right/passenger side uses the corresponding right-side gasket.
Does it include head bolts?
No. Bolts/studs are sold separately and should be replaced.
Will it fit all 2001–2016 6.6L Duramax trucks?
It covers LB7, LLY, LBZ, LMM, and LML. Always verify RPO and side for your VIN, and vans/trucks if applicable.
