Cummins X15 Performance Parts 2017-Present

Why Does Your Cummins X15 Need These Parts?

Cylinder Sealing Is a Scheduled Event, Not an Emergency

A 15-liter working at full load lives on the edge of its sealing hardware. The upper head gasket fights combustion pressure on every power stroke, injector sleeves separate fuel bores from coolant passages with a few millimeters of precision metal, and the rear main seal holds the crankcase against the flywheel housing hour after hour. At overhaul intervals, or at the first sign of coolant loss, fuel in the coolant, or a damp clutch, these are the parts that decide whether the engine comes apart on your schedule or its own.

The Factory Tooling Gap Makes Hard Jobs Harder

Ask any shop that has pressed wet cylinder liners into an ISX block with improvised plates: the liner press installer tool turns a two-hour fight into a clean, even operation with correct counterbore seating and protrusion. The same story repeats at the rear main seal, where the installer and remover tool seats the double-lip seal square without the fold-overs that cause the very leak you are fixing, and at the fuel system, where the injector leak test kit isolates a bad injector before cylinder wash turns a hundred-dollar part into a cylinder of scored liner.

Heat Cycles Eat the Exhaust Side, and the EGR Clock Runs

The X15 exhaust manifold cycles from cold to glowing and back every duty cycle, and ordinary cast iron cracks across those transitions. The studs fight the same thermal growth, breaking when the manifold expands against rusted fasteners. Meanwhile the EGR cooler, the platform's most famous failure point, weeps coolant and recirculates abrasive soot through the intake with every mile. The parts in this collection answer both: manifold hardware built for the cycling, and the Stage 2 delete for rigs whose configuration allows it.

What Can These X15 Parts Solve?

In-Frame Overhaul & Internal Engine Parts

The rebuild core: a heavy-duty upper head gasket set engineered for the X15's extreme cylinder pressures, preventing combustion blow-by and coolant-oil cross-contamination; the injector sleeve cup tube kit with installation tooling that seals the fuel injector bores from the coolant passages, stopping coolant leaks into cylinders and fuel contamination in the cooling system; and a forged steel connecting rod built to endure high torque loads and peak cylinder pressures under heavy-haul conditions without flexing. Together they are the long-block heart of an in-frame overhaul.

Specialized Service & Diagnostic Tools

The cylinder liner press installer tool presses wet liners into the block evenly and without binding, ensuring proper counterbore seating and protrusion. The fuel injector leak test kit isolates individual injectors to detect internal high-pressure leaks, return-flow anomalies, and cracked nozzles before they cause cylinder wash or misfires. And the crankshaft rear main seal installer and remover tool seats and extracts the seal cleanly, keeping the flywheel housing and clutch dry and free from oil contamination.

Fuel System & Engine Management Electronics

The fuel transfer pump draws fuel from the tanks and supplies steady low-pressure feed to the high-pressure circuit, while the precision fuel injectors deliver highly atomized bursts directly into the cylinders for combustion efficiency and fuel economy. The engine actuator gasket seal provides a leak-proof barrier for the electronic VGT and fuel actuators, protecting their internals from oil mist and weather. Around them, the sensor suite, camshaft and crankshaft position, fuel pressure, exhaust gas pressure, and gas temperature, streams real-time data to the ECM to optimize injection timing, turbo vanes, and engine protection.

Exhaust, Turbocharging & Performance Deletes

The multi-piece high-silicon ductile iron exhaust manifold expands and contracts without cracking, with the mounting hardware kit preventing stud breakage under heavy thermal cycling. The V-band 90-degree turbo elbow gives the turbine outlet a smooth, leak-free transition to the downpipe, held by heavy-duty V-band clamps rated for high EGTs and vibration, and the air intake elbow smooths the bends at the manifold connection for higher air velocity, better throttle response, and lower EGTs. The Stage 2 EGR delete kit for CM2250 and CM2350 electronics removes the failure-prone cooler and valve assembly, stopping soot recirculation into the intake.

Cooling, Drive Belt & Air Systems

Two water pump options cover the platform: the 14.9L heavy-duty pump for the ISX and X15 in Peterbilt 389, 567, 579, and 587 applications, and the broad-coverage pump spanning QSZ13, X15, ISX, and ISX15 from 2003-2023. The belt tensioner pulley assembly maintains correct serpentine tension to prevent slippage and protect the alternator, water pump, and fan hub, and the 85mm single cylinder air compressor repair kit rebuilds the compressor's piston, rings, and valves, restoring fast air buildup for the pneumatic brakes a Class 8 lives on.

Shop Cummins X15 Parts by Engine & Fitment Guide

• Upper Head Gasket Set (2007-2019 ISX15/X15) - Fits the 15-liter Cummins in Peterbilt, Kenworth, Freightliner, and Volvo Class 8 trucks. The multi-layer sealing core of any in-frame overhaul.
• Injector Sleeve Cup Tube Kit (2007-2019 15L family) - Fits the ISX, ISX15, QSX15, and X15 in all Class 8 applications. Precision sleeves with installation tooling to seal fuel bores from coolant passages.
• Connecting Rod (2017-2023 ISX15/QSX15) - Fits the current-generation 15-liter. Forged steel rod for heavy-haul torque and peak cylinder pressures.
• Cylinder Liner Press Installer Tool (2007-2019) - Fits ISX and X15 service work. Professional press tool for even wet-liner installation with correct counterbore seating.
• Fuel Injector & Transfer Pump (2004-2021) - Fits the ISX15, QSX15, and X15 fuel system. Precision injectors and the 12V transfer pump that feeds them.
• Sensor Suite (2001-2019) - Camshaft and crankshaft position, fuel pressure for CM871, exhaust gas pressure, and gas temperature sensors covering the ISX engine management family.
• Exhaust Manifold & Mounting Kit (2007-2023) - The CM570 complete replacement manifold and the CM2250/CM2350 mounting hardware kit, high-silicon ductile iron built for thermal cycling.
• V-Band Turbo Elbow & Air Intake Elbow (2007-2019) - Smooth-flow turbo outlet and intake connection elbows for the 15L and 6.7L ISX, lowering backpressure and EGTs.
• Stage 2 EGR Delete Kit (2010-2024 CM2250/CM2350) - Full EGR cooler and valve removal for competition and off-road configurations; requires delete-capable ECM tuning.
• Water Pumps, Belt Tensioner & Air Compressor Kit (2003-2023) - Two pump options across the 14.9L and QSZ13 family, the belt tensioner pulley assembly, and the 85mm air compressor rebuild kit.

Why Choose EGR Performance?

The industry standard for high-performance diesel reliability.

Premium Quality & Rigorous Testing

Our EGR, DPF, and CCV delete kits are engineered from premium-grade materials and subjected to brutal quality control and field testing. Unlike generic alternatives, our products are built to withstand extreme heat and pressure, delivering unmatched durability and long-term stability when your rig needs it most.

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We aren't just selling parts. We live in this industry. With two decades of hands-on experience providing specialized modification solutions for heavy-duty truck owners, our upgrades have been extensively proven across every driving environment, from daily towing to high-performance tracks.

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Thousands of diesel owners trust us to unlock their engine's true potential. Our massive library of positive customer feedback and successful build case studies proves one thing: our kits deliver real horsepower, lower EGTs, and flawless reliability in the real world.

Engine Architecture Notes Behind Cummins X15 Performance Parts

The Cummins X15 is a 15 liter inline six built for line haul work, and the architecture explains why Cummins X15 performance parts focus on airflow, EGR hardware, and service items instead of peak horsepower. The engine runs four valves per cylinder, a gear driven valvetrain, and a high pressure common rail injection system that holds rail pressure far above anything a pickup sees. A variable geometry turbocharger feeds the intake, and the aftertreatment stack behind it carries a diesel particulate filter and selective catalytic reduction dosing that depend on the EGR circuit staying clean.

Electronics matter as much as hardware on these engines. Fitment splits by control module, with CM2250 and CM2350 calibrations covering the engines built from 2010 through 2024, so the same mechanical job can need a different kit depending on the software the truck left the factory with. Soot loading in the EGR cooler is the failure that pushes these engines into derate, which is why cooler service and EGR hardware sit at the center of this collection.

Maintenance Tips for Cummins X15 Performance Parts

Cummins X15 performance parts pay off longest when the engine is watched rather than ignored, and these five habits are the ones worth scheduling.

• Inspect the EGR cooler on a set interval. Soot loading is what sends an X15 into derate, and catching it early keeps the truck earning.
• Confirm the control module before ordering. A CM2250 truck and a CM2350 truck can need different hardware for the same job.
• Monitor boost and exhaust temperature together. A rising exhaust temperature at the same boost means the charge air side is losing ground.
• Service the fuel filtration on a strict schedule. High pressure common rail parts on a 15 liter engine do not forgive dirty fuel.
• Recheck clamps and joints after major service. Long haul vibration works fittings loose over thousands of miles.

Off-Road Use Statement for Cummins X15 Performance Parts

EGR delete and DPF delete hardware in this collection removes factory emissions equipment, and it is not legal for use on a vehicle driven on public roads. Federal law treats removing or defeating an emissions control device as tampering, and the installer accepts that responsibility. Every emissions delete kit sold here is intended for competition and closed-course off-road use only, and it is not approved for street registration, inspection, or daily on-road driving. Street legal hardware such as intake, cooling, fuel filtration, exhaust hardware, and harness protection parts carries no such restriction, so you can run those on a registered vehicle without issue.

FAQs About Cummins X15 Performance Parts

What parts does this Cummins X15 collection cover?

Five departments for the 15-liter family, the X15 and its ISX15 and QSX15 predecessors from 2007 through the current trucks. In-frame overhaul parts including the head gasket set, injector sleeves, and connecting rods; professional service tools including the liner press and injector leak test kit; the fuel system from transfer pump to injectors plus the engine management sensors; the exhaust side with manifolds, turbo elbow, intake elbow, and the Stage 2 EGR delete; and the cooling, belt, and air compressor hardware.

If you do not see the piece you need, ask our 24/7 support before assuming it is unavailable; heavy-duty coverage expands constantly.

What is included in an in-frame overhaul on an X15?

The core sealing and rotating pieces that come out during an in-frame: the upper head gasket set, the injector sleeve cup tubes, the connecting rods, and fresh seals front to rear, with wet cylinder liners pressed in using the proper installation tool. Our collection carries the heart of that list directly.

The practical answer for most owner-operators is that the in-frame happens around 500,000 to 700,000 miles, and ordering the gasket set, sleeves, and rods together keeps the engine bay from becoming a waiting room for three separate backorders.

Why do injector sleeves fail on the X15?

The sleeve cup tubes seal each fuel injector bore against the coolant passages surrounding it, and they live in the hottest chemistry in the engine. Cavitation, corrosion, and heat cycling eventually pit or crack a sleeve, and the symptoms are unmistakable: coolant loss with no visible leak, fuel sheen in the coolant reservoir, or white smoke from a cylinder drinking antifreeze.

The injector sleeve cup tube kit replaces all of them with precision-manufactured pieces plus installation tooling, done during injector service so the bores only come apart once. It is cheap insurance whenever injectors are out of the engine for any reason.

What service tools are worth having for X15 work?

The three in this collection pay for themselves on the first job. The cylinder liner press installer tool presses wet liners into the block evenly and without binding, guaranteeing correct counterbore seating and protrusion instead of the cocked liner that wipes out a fresh gasket. The crankshaft rear main seal installer and remover tool seats the double-lip seal square, avoiding the folded lip that recreates the leak you were fixing.

The fuel injector leak test kit isolates each injector to catch internal high-pressure leaks, return-flow anomalies, and cracked nozzles before they wash a cylinder down with fuel and score the liner. None of these jobs forgive improvisation, which is exactly why the tools exist.

Why do X15 exhaust manifolds crack?

Thermal cycling. The manifold goes from ambient to glowing red across every working day, and the growth and shrinkage fatigues ordinary cast iron until it cracks between runners or at the flange. Broken studs compound it: corroded fasteners fight the manifold's expansion and shear instead of allowing movement.

Our replacement is multi-piece high-silicon ductile iron, a material chosen because it expands and contracts with the heat instead of fighting it, and the CM2250/CM2350 mounting hardware kit replaces the studs with hardware sized for the cycling. Together they break the crack-and-replace loop the factory design traps trucks in.

What does the Stage 2 EGR delete do on an X15?

It removes the EGR system entirely: the cooler, the valve, and the associated plumbing, sealed with plates and plugs. On the CM2250 and CM2350 electronics that means no more coolant weeping from a cracked cooler and no more abrasive soot recirculated through the intake tract, with cleaner oil and lower operating temperatures as the practical results.

Two requirements come with it. The delete demands ECM tuning through Cummins INSITE to shut off the EGR strategies, and it is legal only for competition and closed-course off-road use, never for regulated on-highway trucks. Confirm your configuration and duty cycle with our support team before ordering.

Which sensors keep the X15's engine management running?

The suite the ECM thinks with: camshaft and crankshaft position sensors for timing and synchronization, the fuel pressure sensor for the high-pressure circuit on CM871 and later electronics, the exhaust gas pressure sensor for EGR and turbo control, and the gas temperature sensor for aftertreatment and protection strategies.

When one drifts, the symptoms are vague, rough running, derates, poor fuel economy, and the fault code is the only honest witness. Replacing the failed sensor rather than chasing the symptom is the difference between a fifty-dollar fix and a misdiagnosed injector job.

When should the water pump or belt tensioner be replaced?

The water pump on a working X15 is a wear item, and the smart move is replacing it during any major service rather than waiting for the weep stain on the fan shroud. We carry two options: the heavy-duty 14.9L pump for ISX and X15 applications including Peterbilt 389, 567, 579, and 587, and a broad-coverage pump spanning QSZ13, X15, ISX, and ISX15 from 2003 through 2023.

The belt tensioner belongs in the same conversation. A tired tensioner lets the serpentine belt slip and chirp, and the slack beats up the alternator, water pump, and fan hub bearings. Swapping the tensioner pulley assembly when the belt comes off is how one accessory job stays one job.

Why rebuild the air compressor instead of replacing it?

The engine-driven air compressor feeds the truck's pneumatic brakes, and its piston, rings, and valves wear like any other hard-working assembly. The 85mm single cylinder repair kit rebuilds those internals for a fraction of a complete compressor, restoring fast air buildup and dry, oil-free delivery to the air tanks.

The rebuild is straightforward for any shop already comfortable with engine work, and it eliminates the slow air-up, cycling unloader, and oil carryover that mark a compressor on its way out. On a system as safety-critical as brakes, a fresh kit is peace of mind measured in pump-down time.

Are these X15 parts street legal, and what is the warranty?

It splits cleanly. Overhaul parts, tools, fuel system components, sensors, manifolds, elbows, water pumps, tensioners, and the air compressor kit are emissions-neutral service hardware, legal everywhere. The Stage 2 EGR delete kit is the exception: emissions deletes are for competition and closed-course off-road use only, and removing them from a regulated on-highway engine violates the Clean Air Act with substantial EPA penalties.

Fitment spans the 2007-2024 ISX15, QSX15, and X15 family with ECM-specific pieces keyed to CM570, CM871, CM2250, and CM2350 electronics, so confirm your engine serial or contact our 24/7 support for the match. Every order ships free from our US warehouses, carries a 1-year warranty, and is backed by a 45-day return policy if the fitment is not right.