The SPOOLOGIC Exhaust Manifold Install Kit SL-300-032 is the complete gasket-and-hardware kit for the exhaust manifolds, up-pipes, and EGR valve flange on 2017-2026 6.6L Duramax L5P and L5D trucks — everything you'll touch when the manifolds come off, in one box. Two large MLS manifold gaskets, two manifold-to-up-pipe gaskets, the EGR valve flange gasket, sixteen manifold studs with spacers and nuts, plus up-pipe and EGR valve hardware. 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, up-pipe, and EGR valve 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 studs, spacers, and nuts — live in the hottest, most thermally cycled part of the engine. Threads stretch, the spacer faces deform, and the nut underhead surface loses its bearing area after one heat cycle at full EGT. New hardware is cheap insurance and torques predictably the second time.
• Up-pipe bolts and washers — same story as manifold hardware. Single-use by design on hot-side exhaust joints.
• EGR valve flange gasket and bolts — the EGR valve mounts straight to the exhaust manifold and sees the same exhaust gas the cylinders just made. Reusing the gasket or bolts here gives you a soot leak right next to the valve body.

Component Breakdown — What Each Piece Seals

• 2 exhaust manifold gaskets — large multi-layer steel gaskets, one left and one right, that seal each cylinder head to its exhaust manifold across all eight ports.
• 2 exhaust manifold-to-up-pipe gaskets — triangular MLS gaskets that seal the manifold outlet to the up-pipe on each bank.
• 1 EGR valve-to-exhaust manifold gasket — rectangular flange gasket that seals the EGR valve to the exhaust manifold.
• 16 exhaust manifold studs — thread into the cylinder head and carry the manifold clamp load. Black oxide finish with thread locker pre-applied on the cylinder-head end.
• 16 exhaust manifold spacers — cylindrical spacers that ride on the studs between the manifold and the nut to set the correct stack height.
• 16 exhaust manifold nuts — flanged hex nuts that clamp the manifold down on the studs.
• 6 up-pipe bolts + 6 up-pipe washers — bolts and flat washers that hold both manifold-to-up-pipe joints together.
• 4 EGR valve bolts + 4 EGR valve washers — bolts and flat washers that hold the EGR valve to the exhaust manifold.

Material Technology — Why Each Material Was Chosen

• Multi-layer steel (MLS) construction — all five 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.
• Black oxide stud-spacer-nut assemblies — the manifold studs are heat-treated to the OE grade specification, finished in black oxide for corrosion resistance, and come with thread locker pre-applied on the cylinder-head end. The spacers and flanged nuts are matched to the stud for correct stack height and clamp load.
• Heat-treated up-pipe and EGR valve bolts — bolts are heat-treated to the OE grade specification and finished in black oxide. The flat washers are hardened steel so they spread the clamp load evenly across the flange.

Install Notes

• Do not reuse any gasket, stud, spacer, nut, bolt, or washer 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 manifold studs, the up-pipe bolts, and the EGR valve bolts.
• 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 install kit for 2017-2026 L5P and L5D Duramax
• Multi-layer steel construction on all five gaskets
• 16 manifold studs with matched spacers and flanged nuts
• Thread locker pre-applied on the cylinder-head end of every stud
• Heat-treated up-pipe and EGR valve hardware
• Covers manifold-to-head, manifold-to-up-pipe, and EGR valve-to-manifold joints
• Backed by a 1-Year Limited Warranty

What’s Included

• 2 exhaust manifold gaskets (left + right)
• 2 exhaust manifold-to-up-pipe gaskets
• 1 EGR valve-to-exhaust manifold gasket
• 16 exhaust manifold studs
• 16 exhaust manifold spacers
• 16 exhaust manifold nuts
• 6 up-pipe bolts
• 6 up-pipe washers
• 4 EGR valve bolts
• 4 EGR valve washers

Fits 2017-2026 6.6L Duramax

• 2017 – 2026 Chevrolet Silverado GMC Sierra 2500 3500 6.6L Duramax L5P
• 2019 – 2026 Chevrolet Silverado 4500 5500 6500 6.6L Duramax L5D

Turbo Applications

This install kit fits the following factory turbocharger:

• BorgWarner B2 (BV50) (2017-2026 6.6L Duramax L5P)

1-Year Limited Warranty

Every SPOOLOGIC Exhaust Manifold Gasket 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.