The SPOOLOGIC Turbo Gasket Kit SL-310-028 is a complete 15-piece R&R gasket, seal, crush washer, and O-ring kit for 2024-2026 6.6L Duramax L5P and L5D trucks — everything you’ll touch when the turbo comes off, in one box. Built from multi-layer steel construction, green Viton fluoroelastomer, and coated steel oil-line gaskets so the seal you put back in is at least as good as what came out — usually better. Backed by a 1-Year Limited Warranty.

This is the kit to put on the bench before you start the job. Pulling the turbo on the 2024-2026 L5P means breaking the turbo flange, the pedestal mount, the oil supply and drain lines, the coolant supply and return, the PCV line, the catalytic converter joint, the intake plenum, and the throttle valve — every one of those joints uses a one-time-use gasket, crush washer, or O-ring that should not be reused. Heat-cycled multi-layer steel has already crushed to fit the original surface. Viton O-rings have taken a set and lost their elasticity. Crush washers are crushed — that’s the entire point of a crush washer. Reusing any of it is how you end up with an oil leak, a coolant weep, an intake-side boost leak, or a slow exhaust leak that puts soot on the firewall and forces you to pull the whole thing apart again.

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

Turbo R&R 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 — these are stacked thin steel sheets bonded with a flexible elastomer coating. On first torque-up the layers crush down to mate to the exact surface roughness of the flange they’re sealing. Once crushed, they cannot crush again to a new surface (or even back to the same surface after thermal cycling has moved things 0.001” in either direction). Reused MLS gaskets are the #1 cause of post-turbo-job oil seepage at the pedestal and exhaust leaks at the flange.
• Green Viton O-rings and molded seals — Viton is a fluoroelastomer rated for 400°F continuous service, which is why it’s used everywhere on a modern diesel that sees oil temp, coolant temp, or radiant turbo heat. But Viton takes a compression set the moment it’s installed — the rubber permanently deforms to fit the groove and the mating surface. A used O-ring that looks fine to your eye has already lost most of its sealing pre-load. It will not seal a second installation reliably.
• Crush washers — these work by plastically deforming on first torque. A used crush washer is a flat washer. It cannot seal high-pressure oil at the turbo feed banjo.
• Coated oil-line gaskets — the black coating on the oil drain and feed gaskets is a fuel- and oil-resistant elastomer bonded to a steel core. The coating compresses on first torque to fill machining marks in the casting. Reuse and it’s already crushed flat — no fill, no seal, oil leak.

Buying one gasket at a time from the dealer for a turbo R&R adds up fast and still leaves you waiting on the one that didn’t ship overnight. The SL-310-028 has all 15 pieces in one box, OE-quality or better.

Component Breakdown — What Each Piece Seals

Here’s exactly what’s in the kit and where each piece lives:

• 2 turbo oil supply line crush washers — copper crush washers that seal the high-pressure oil feed banjo bolt at both ends of the supply line. These see full engine oil pressure (~50-80 psi) and full oil temp. Crush washers must be replaced any time the banjo is broken loose — non-negotiable.
• 1 turbo oil supply line gasket — seals the supply line where it transitions between the turbo center section and the feed line itself.
• 2 upper oil drain line gaskets — seal the drain line at the turbo center section. The drain line is low pressure but high volume — a leak here dumps used oil onto the hot turbine housing and the catalytic converter, which is where you get the smoke-on-startup complaint.
• 1 lower oil drain line gasket — seals the bottom of the drain line where it returns to the block. Same story: a leak here paints the side of the block with oil and shows up in your driveway.
• 1 PCV line to turbo gasket — the positive crankcase ventilation system routes blow-by gases from the valley back into the intake side of the turbo. This gasket sees oil vapor, fuel vapor, and intake vacuum — a leak here is a boost leak (turbo sucks atmospheric air past the gasket) and a crankcase pressure leak.
• 2 turbo coolant line gaskets — 1 supply, 1 return — the L5P uses a water-cooled center section, which is why these motors run their turbos so cool. The coolant supply and return lines each have a gasket at the turbo connection. A coolant leak here drops onto the turbine housing and flashes to steam — you’ll see white smoke, lose coolant, and not know where it’s going.
• 1 turbocharger to turbo pedestal gasket — multi-layer steel gasket between the turbocharger and the pedestal it sits on. This is the gasket that separates engine oil and coolant passages in the pedestal from the outside world. A leak here is the worst kind — mixed oil and coolant on the engine valley.
• 1 turbocharger to catalytic converter gasket — the exhaust joint between the turbine housing outlet and the cat. This sees 1,000°F+ exhaust gas under boost. A leak here is loud, sooty, and ruins the cat’s thermal management.
• 2 intake plenum gaskets — seal the intake plenum to the cylinder head. Boost-side leaks here cost you boost pressure, MAF readings get scrambled, and the truck runs lean.
• 2 throttle valve gaskets — the throttle valve assembly bolts to the intake plumbing. Kit includes both throttle valve gaskets used across the application range — install the one that fits your truck.

Material Technology — Why Each Material Was Chosen

• Multi-layer steel (MLS) construction — the turbo flange and pedestal gaskets are MLS, not composite. MLS gaskets use three or more thin steel layers with an elastomer coating, each layer free to flex independently as the mating surfaces grow and shrink with heat. This is the same construction GM specifies on the OE gasket. Composite or copper-only gaskets in this location will not survive the thermal cycling.
• Green Viton fluoroelastomer — the molded seals and O-rings are Viton, the industry-standard fluoroelastomer for hot oil, hot coolant, and hot air service. Viton is rated for 400°F continuous and 500°F intermittent — well beyond the operating temp of any fluid passage on this engine. Standard nitrile (black rubber) O-rings would harden, crack, and leak within a few heat cycles.
• Black coated oil-line gaskets — the small black 4-hole and 2-hole gaskets are a steel core with a bonded fluoroelastomer coating. The steel handles the bolt clamp load without crushing the gasket flat; the coating fills machining marks on the casting surface. This is the construction that actually seals an oil leak — uncoated steel gaskets in this location are a known leak path.
• Copper crush washers — soft copper plastically deforms on first torque to fill the irregular surface between banjo bolt, banjo, and turbo housing. Copper is used here (instead of aluminum or steel) because it plastically deforms predictably without work-hardening, and because it tolerates the heat.

Install Notes

• Do not reuse any gasket, seal, O-ring, or crush washer in this kit — every piece is single-use by design.
• Clean every mating surface before installing the new gasket. MLS gaskets cannot bridge over carbon deposits, machining burrs, or old gasket material left on the flange. A razor scraper and brake clean is the minimum.
• Follow the GM service manual torque specs and sequence — the turbo flange and pedestal bolts are torque-to-yield in some applications. Don’t guess.
• Replace any cracked or warped hardware — up-pipe studs, banjo bolts, and turbo mounting bolts all live in the same heat as the gaskets and don’t last forever.

Fits 2024-2026 6.6L Duramax

• 2024 – 2026 Chevrolet Silverado GMC Sierra 2500 3500 6.6L Duramax L5P
• 2024 – 2026 Chevrolet Silverado 4500 5500 6500 6.6L Duramax L5D

Replaces Factory OEM Part Numbers

• GM OEM: 12700564, 12737099, 12737100

What’s Included

• 2 turbo oil supply line crush washers
• 1 turbo oil supply line gasket
• 2 upper oil drain line gaskets
• 1 lower oil drain line gasket
• 1 PCV line to turbo gasket
• 2 turbo coolant line gaskets (1 supply, 1 return)
• 1 turbocharger to turbo pedestal gasket
• 1 turbocharger to catalytic converter gasket
• 2 intake plenum gaskets
• 2 throttle valve gaskets (install the one that fits your application)

Features

• Complete 15-piece turbo R&R gasket kit for 2024-2026 L5P / 2024-2025 L5D Duramax
• Multi-layer steel construction on the turbo flange and pedestal gaskets
• Green Viton fluoroelastomer O-rings and molded seals — 400°F continuous service rated
• Coated steel oil drain and feed gaskets — fluoroelastomer-coated for proper seal on cast surfaces
• Copper crush washers on the high-pressure oil supply banjo
• Covers every joint broken during a turbo R&R — no extra trips to the dealer
• Backed by a 1-Year Limited Warranty

1-Year Limited Warranty

Every SPOOLOGIC turbo gasket kit is covered by a 1-Year Limited Warranty against defects in materials and workmanship from the date of purchase. Warranty covers replacement of the part only. Warranty does not cover labor, towing, downtime, 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.