Cylinder Heads & Related Components for Cummins QSX Engines

The Cummins QSX engine is known for delivering reliable horsepower in some of the most demanding industrial, agricultural, and power generation applications. At the heart of its performance lies a robust cylinder head assembly designed for durability, heat resistance, and long service intervals. Whether you're conducting a top-end rebuild or addressing a failed valve, Diesel Pro Power provides high-quality QSX cylinder head components to keep your engine operating at peak performance.

We support thousands of diesel professionals with fast shipping, excellent service, and unmatched parts availability. Explore our full inventory of new cylinder heads, valve train components, seals, guides, injector tubes, and more for Cummins QSX engines below.

New Cylinder Head Assembly for Cummins QSX

Diesel Pro Power offers new cylinder heads for the QSX engine with all valves pre-installed for convenience and reliability. These cylinder heads are built to meet or exceed OEM specifications, ensuring a direct-fit replacement for engines with dual overhead camshaft configurations.

Each head is pressure-tested and ready for installation. They are manufactured from high-strength cast iron to withstand the extreme combustion temperatures and pressures typical of heavy-duty applications. Camshafts are not included and must be installed separately. These heads are ideal for equipment undergoing a full top-end refresh or when replacing a damaged or cracked unit.

Cylinder Head Bolt Kits

When replacing a QSX cylinder head, it’s essential to use new head bolts to ensure proper torque and clamping force. Diesel Pro Power provides complete head bolt kits specifically designed for Cummins QSX and ISX engines. These kits include all the necessary bolts to secure the cylinder head to the block, with consistent quality and correct length specifications for dual overhead cam configurations.

Using a fresh set of bolts prevents head gasket failures due to uneven torque distribution and helps maintain proper combustion sealing for high-load environments.

Intake and Exhaust Valves

The intake and exhaust valves in the QSX cylinder head are critical to the engine's breathing and performance. Intake valves control the flow of air into the combustion chamber, while exhaust valves manage the removal of spent gases. Diesel Pro Power supplies high-quality replacement valves that match OEM metallurgy and heat treatment standards, ensuring longevity and thermal resistance.

Each valve is precision-machined for a perfect fit and proper seating against the valve seats, helping maintain optimal compression and fuel efficiency.

Valve Kits & Related Hardware

We also offer valve kits that may include both intake and exhaust valves, stem seals, and valve locks or keepers. These kits are ideal for complete valve replacement jobs where existing components show signs of wear, pitting, or burning.

Pairing new valves with new seals and locks reduces oil consumption, improves compression, and prevents premature valve guide wear.

Injector Tube Kits

Cummins QSX engines use high-pressure fuel injector tubes that deliver fuel directly into the combustion chamber. These injector tubes are mounted inside the cylinder head and are essential for proper fuel delivery and sealing under high pressures.

Diesel Pro Power offers complete injector tube kits that include the aluminum tubes and seals required for installation. Replacing worn or leaking injector tubes helps eliminate compression loss, poor starting, or fuel-in-oil contamination. Kits are available with or without seals depending on your rebuild needs.

Injector Tube Seals

Injector tube seals are vital in preventing leaks between the fuel system and the coolant passages or combustion chamber. Even minor wear or cracking in these seals can lead to engine misfires or internal coolant contamination. Always replace these seals when installing new tubes or servicing the injector bores.

Valve Cover Gaskets & Gasket Sets

Whether your QSX engine is equipped with an EGR system or not, Diesel Pro Power offers upper gasket sets tailored to your engine’s configuration. These kits typically include intake and exhaust manifold gaskets, valve cover gaskets, and additional top-end seals necessary when removing and replacing the cylinder head.

Valve cover gaskets specifically designed for QSX applications provide a secure seal around the valve train to prevent oil leaks and maintain crankcase ventilation efficiency. Choose the correct gasket style based on the engine model year and EGR status.

Valve Springs and Retainers

Valve springs are responsible for ensuring valves close tightly and consistently under high-speed operating conditions. Over time, these springs may weaken, leading to valve float, misfires, or a drop in engine performance. Diesel Pro Power provides valve springs engineered to handle the stress of high-load operation in QSX engines.

Retainers and keepers should be inspected and replaced during a top-end rebuild to maintain proper valve spring tension and prevent premature valve failure.

Valve Seats and Inserts

Cylinder head inserts or valve seats provide a hardened contact surface for intake and exhaust valves. Replacing worn or pitted valve inserts ensures proper sealing, improved airflow, and resistance to heat erosion. Diesel Pro Power supplies precision-machined inserts for both intake and exhaust valves on QSX heads, ensuring consistent seating pressure and a long service life.

Valve Guides and Seals

Valve guides support the stem of the valve as it moves within the cylinder head, maintaining alignment and reducing side loading. Excessive valve guide wear can lead to oil consumption, valve stem damage, and reduced compression.

Valve seals, installed at the top of each guide, prevent oil from seeping into the combustion chamber. Diesel Pro Power offers both guides and seals for Cummins QSX engines, allowing for comprehensive head servicing and restoration of proper valve operation.

Noise & Vibration Isolators

QSX engines utilize vibration isolators mounted near the valve cover area to minimize noise and resonance through the upper engine structure. These components vary slightly depending on engine production year. Isolators for 2003–2009 models differ in design from those used in engines produced from 2010 onward.

Replacing worn or damaged isolators reduces cabin noise, improves operator comfort, and prevents stress fractures in engine brackets or valve cover mounting points.

Temperature Switches

Although not mounted directly on the cylinder head, temperature switches are often located nearby and are essential for monitoring coolant temperature. Diesel Pro Power offers reliable switches that activate at factory-set temperatures, helping to trigger engine cooling systems or safety shutdowns as required.

These switches are compatible with multiple heavy-duty engine platforms, including Cummins QSX, and are an important part of the thermal protection system in high-horsepower engines.

When to Replace Your Cummins QSX Cylinder Head

There are several signs that it may be time to replace your QSX cylinder head:

• Coolant in the oil or vice versa, which can indicate a cracked head or failed injector tube seal.

• Loss of compression in one or more cylinders.

• Visible cracks or warping on the head surface.

• Persistent valve seat erosion or damage beyond re-machining.

• Excessive oil consumption, especially after valve seal and guide replacement.

If you're seeing any of the symptoms above, it’s often more cost-effective to replace the entire cylinder head assembly rather than attempting repeated repairs on a compromised casting.

Benefits of Choosing Diesel Pro Power for QSX Cylinder Head Components

• All major components in stock, including valves, seals, bolts, and gaskets.

• New cylinder heads with valves pre-installed for easy top-end rebuilds.

• Fast global shipping to get your engine running again quickly.

• Bilingual support in English and Spanish for international customers.

• Trusted by over 40,000 customers worldwide, including mechanics, fleet operators, and engine rebuilders.

How to Ensure Compatibility With Your QSX Engine

The Cummins QSX engine series comes in multiple configurations, so it's essential to verify a few details before ordering:

• Whether your engine uses a single or dual overhead cam setup. QSX engines typically feature dual camshafts.

• Whether your engine has an EGR system, as this affects gasket kit selection.

• The year of manufacture, which impacts valve cover gasket and vibration isolator compatibility.

Our team is available to help confirm compatibility using your engine serial number or CPL number.