Product Description
MAHLE 54584 is a left-side, Grade B (1.00 mm) multi-layer steel (MLS) cylinder head gasket for the 2001–2016 GM 6.6L Duramax. Built to OE specs for reliable sealing on stock or tuned engines.
- Side: Left (driver side)
- Material: MLS
- Thickness: 1.00 mm (Grade B)
- Typical bore: ~4.14 in (≈105.4 mm)
- Warranty: 1-Year Limited
Fitment
- GM 6.6L Duramax V8 (LB7 2001–2004, LLY 2004.5–2005, LBZ 2006–2007, LMM 2007.5–2010, LML 2011–2016)
Cross Reference Numbers
- OE GM: 12637786 (Left, Grade B, 1.00 mm) — supersessions: 98030632, 98045059
- GTIN/UPC (MAHLE): 027067719911
What’s Included
(1) Left-side MLS head gasket. Head bolts/studs not included—replace TTY bolts or upgrade to studs during service.
Related/Alternatives (Left-side)
- Grade A (0.95 mm): MAHLE 54583 — shop 54583
- Grade C (1.05 mm): MAHLE 54585 — shop 54585
FAQ
Will this fit my 6.6L Duramax?
Yes. It fits LB7, LLY, LBZ, LMM, and LML engines from 2001–2016.
Is this the left or right gasket?
This is the left (driver-side) gasket. Right-side uses a different part number.
How do I choose Grade A/B/C?
Use the thickness specified by GM service info or measured piston protrusion. Grade B = 1.00 mm.
Do I need new bolts or studs?
Yes—factory bolts are torque-to-yield. Replace them or upgrade to ARP studs for repeatable clamping.
Pro Tip
Verify head/block surface finish (RA) for MLS gaskets and follow the OE torque sequence. Consider upgrading to ARP 230-4201 head studs during the job.
