The SPOOLOGIC Exhaust Manifold Install Kit SL-300-031 is the complete gasket-and-hardware kit for the exhaust manifolds and up-pipes on 2001-2016 6.6L Duramax LB7, LLY, LBZ, LMM, and LML trucks — everything you'll touch when the manifolds come off, in one box. Two large MLS manifold gaskets, four MLS up-pipe gaskets, sixteen exhaust manifold bolts, and twelve up-pipe bolts. Available with bolts sized for OE-style manifolds or aftermarket manifolds — choose the variant that matches the manifolds you're installing. Backed by a 1-Year Limited Warranty.

Every part in this kit is single-use by design. MLS gaskets crush down to the exact roughness of the flange on first torque, and exhaust manifold bolts stretch and warp after one heat cycle at full EGT. Reusing any of them is the #1 cause of post-job manifold ticks and hot-side leaks — that’s why we built the kit around one-and-done, install-it-right hardware.

Common Exhaust Manifold Install Failure Symptoms

• Ticking or hissing at idle — reused exhaust manifold gasket that already crushed on the previous install, leaking exhaust at the port.
• Loud tick from the engine valley — leaking manifold-to-up-pipe or up-pipe-to-turbo joint on a reused MLS gasket.
• Slow spool, low boost, or high EGT — an exhaust leak upstream of the turbo bleeding off gas before it reaches the turbine wheel.
• Bolt backed out or snapped at torque — reused manifold or up-pipe hardware with stretched threads or a deformed underhead.

Why You Replace All of This — Not Just the One That’s Leaking

Exhaust manifold and up-pipe hardware and gaskets are not designed to be reused. Here’s what’s actually happening to the parts you’re tempted to put back:

• Multi-layer steel (MLS) gaskets — stacked thin steel sheets bonded with an elastomer coating. On first torque-up the layers crush down to mate the exact surface roughness of the flange. Once crushed they cannot crush again to a new surface. Reused MLS gaskets are the #1 cause of post-job exhaust leaks at the manifold and up-pipe.
• Exhaust manifold bolts — live in the hottest, most thermally cycled part of the engine. Threads stretch, heads warp, and the underhead bearing surface deforms after one heat cycle at full EGT. New hardware is cheap insurance and torques predictably the second time.
• Up-pipe bolts — same story as manifold bolts. Single-use by design on hot-side exhaust joints.
• OE-style vs aftermarket manifolds — the two manifold designs use different bolt sizes. Using the wrong bolt either bottoms out before clamp load is reached or strips the head threads. Pick the variant that matches your manifolds.

Component Breakdown — What Each Piece Seals

• 2 exhaust manifold gaskets — large multi-layer steel gaskets that seal each cylinder head to its exhaust manifold. This joint sees full exhaust gas temperature and pressure across all eight ports.
• 2 manifold-to-up-pipe gaskets — MLS gaskets that seal the exhaust manifold outlet to the up-pipe on each bank.
• 2 up-pipe-to-turbo gaskets — triangular MLS gaskets that seal the up-pipe to the turbo inlet on each bank.
• 16 exhaust manifold bolts — heat-treated bolts that hold both manifolds to the cylinder heads. Variant-specific — OE-style or aftermarket.
• 12 up-pipe bolts — heat-treated bolts that hold both up-pipe ends to the manifold and turbo flanges.

Material Technology — Why Each Material Was Chosen

• Multi-layer steel (MLS) construction — all six gaskets in this kit are MLS, not composite. MLS uses three or more thin steel layers with an elastomer coating, each layer free to flex independently as the joint grows and shrinks with heat. This is the construction that survives 1,200°F+ exhaust gas temperatures on the hot side of the turbo.
• Heat-treated exhaust manifold bolts — the manifold bolts are heat-treated to the OE grade specification for sustained high-temperature clamp load without stretching or backing out. Sized for the manifold variant you select.
• Heat-treated up-pipe bolts — same heat-treat spec as the manifold bolts, sized for the up-pipe flanges.

Install Notes

• Confirm your manifold variant before ordering — OE-style and aftermarket manifolds take different exhaust manifold bolts.
• Do not reuse any gasket or bolt in this kit — every piece is single-use by design.
• Clean every mating surface before installing the new gaskets. MLS gaskets cannot bridge over carbon deposits, machining burrs, or old gasket material. A razor scraper and brake clean is the minimum.
• Follow the GM service manual torque specs and sequence for the exhaust manifold bolts and the up-pipe bolts at both ends.
• Inspect the manifolds and up-pipes themselves for cracks at the ports, bellows, or flange welds before reinstalling — a cracked manifold or up-pipe will leak past any gasket.

Features

• Complete exhaust manifold and up-pipe install kit for 2001-2016 LB7 / LLY / LBZ / LMM / LML / LGH Duramax
• Variable product — choose OE-style or aftermarket manifold bolts to match your manifolds
• Multi-layer steel construction on all six gaskets
• Heat-treated exhaust manifold bolts and up-pipe bolts
• Covers manifold-to-head, manifold-to-up-pipe, and up-pipe-to-turbo joints
• Backed by a 1-Year Limited Warranty

What’s Included

• 2 exhaust manifold gaskets
• 2 manifold-to-up-pipe gaskets
• 2 up-pipe-to-turbo gaskets
• 16 exhaust manifold bolts (OE-style or aftermarket — variant-specific)
• 12 up-pipe bolts

Fits 2001-2016 6.6L Duramax LB / 6.6L Duramax LLY LMM LGH

• 2001 – 2016 Chevrolet Silverado GMC Sierra 2500 3500 6.6L Duramax LB7 LLY LBZ LMM LML
• 2006 – 2016 Chevrolet Express GMC Savana 2500 3500 4500 6.6L Duramax LLY LMM LGH

Turbo Applications

This install kit fits the following factory turbochargers:

• Garrett GT3788VA (2004.5-2016 6.6L Duramax LLY/LBZ/LMM/LML/LGH)
• IHI RHG6 (2001-2004 6.6L Duramax LB7)

1-Year Limited Warranty

Every SPOOLOGIC Exhaust Manifold Gaskets / Bolts Kit is covered by a 1-Year Limited Warranty against defects in materials and workmanship for the original purchaser. To initiate a warranty claim, the kit must first be shipped back to SPOOLOGIC at the customer’s expense for inspection. If SPOOLOGIC determines the kit is defective in materials or workmanship, a replacement will be shipped at SPOOLOGIC’s cost. Warranty does not cover labor, downtime, towing, consequential damages, failures caused by improper installation, failures caused by dirty or damaged mating surfaces, reuse of any kit component, or use outside the listed fitment.