Cummins 6CTA Gaskets and Sealants Catalog

When it comes to maintaining the durability, reliability, and performance of the Cummins 6CTA engine, ensuring a proper seal across all components is essential. Gaskets, O-rings, and sealants play a critical role in controlling combustion, coolant flow, lubrication, and air intake/exhaust systems. Diesel Pro Power offers a complete line of high-quality replacement gaskets and sealing products engineered specifically for Cummins 6CTA 8.3L engines—trusted in marine, industrial, and generator set applications worldwide.

Below is a detailed breakdown of our 6CTA-compatible gaskets and sealant components, each designed for perfect fitment and long-lasting performance under high temperature and pressure conditions.

Complete Gasket Sets for Cummins 6CTA

Upper Gasket Set – Standard (450 HP and Below)

Our Cummins 6CTA Upper Gasket Set includes all major gaskets needed for the cylinder head and top-end rebuild. This set supports engines rated up to 450 horsepower and includes:

• Head gasket
  
  

• Intake and exhaust manifold gaskets
  
  

• Valve cover gasket
  
  

• Thermostat gasket
  
  

• Injector O-rings
  
  

• Other critical seals for proper combustion and fluid containment
  
  

Using a matched upper set eliminates the guesswork and ensures tight sealing during head and valve component servicing.

Lower Gasket Set – Full Coverage for the Bottom-End

The Lower Gasket Set for Cummins 6CTA engines includes seals for:

• Oil pan
  
  

• Rear main seal
  
  

• Front crankshaft seal
  
  

• Oil pump gasket
  
  

• Water pump mounting gasket
  
  

• Fuel transfer pump gasket
  
  

• Oil cooler gaskets
  
  

• Gear housing gaskets
  
  

This comprehensive kit supports full bottom-end rebuilds and is designed to withstand oil pressure and crankcase vibration common in 6CTA diesel engines.

Cylinder Head Gasket and Related Seals

Cummins Standard Head Gasket – For 230 HP and Below

This critical component ensures a secure seal between the engine block and the cylinder head. Our high-performance head gasket is designed for Cummins 6C8.3 and 6CT8.3 engines up to 230 horsepower. It is manufactured with multi-layer steel and graphite composite materials to provide maximum durability under pressure.

Applications:

• Marine engines
  
  

• Industrial gensets
  
  

• Hydraulic pumps
  
  

• Agricultural tractors
  
  

Gaskets for Air Handling Systems

Exhaust Manifold Gaskets – 6 Per Engine

Cummins 6CTA engines use six individual exhaust manifold gaskets, one for each cylinder. These are high-temperature, precision-cut gaskets designed to seal the manifold to the cylinder head, preventing exhaust leaks and ensuring proper turbo performance.

Key Features:

• Steel reinforced
  
  

• Designed for high-heat cycles
  
  

• Corrosion-resistant
  
  

Exhaust Manifold Outlet Connection Gasket

This gasket seals the outlet of the exhaust manifold where it connects to the turbocharger or exhaust downpipe. An effective seal here is critical to prevent soot leakage, backpressure imbalance, and reduced turbo efficiency.

Turbo Mounting Gasket – For Water-Cooled Turbos

This specialized gasket fits between the turbocharger and the exhaust manifold or elbow on water-cooled Cummins 6CTA setups. It is designed for thermal resistance and vibration endurance, helping maintain turbo efficiency.

Intake System Gaskets

Intake Connection Gasket – 6C, 6CT, 6CTA, ISC, QSC

The intake connection gasket ensures a tight seal between the intake manifold and cylinder head, preventing unmetered air intrusion which can affect fuel combustion and engine timing. Precision cut and made from composite material for optimal airflow integrity.

Valve Train and Rocker Area Gaskets

Valve Cover Gasket – Standard Rubber Profile

A reliable valve cover gasket prevents oil seepage from the cylinder head cover. Our Cummins 6CTA valve cover gaskets are designed with temperature- and oil-resistant materials for durability even under prolonged engine operation.

Water Pump and Marine Cooling System Gaskets

Marine Water Pump Mounting Gasket

This gasket forms the seal between the raw water pump and engine block. Crucial for preventing saltwater leakage and ensuring reliable pump suction.

• Compatible with Cummins 6CTA marine engines
  
  

• Composite design resists salt corrosion
  
  

• Direct-fit for easy installation
  
  

Marine Water Pump O-Ring Set

Two high-pressure O-rings seal the inlet and outlet of the marine raw water pump. These are made from high-performance rubber to resist both chemical and thermal degradation.

Used in:

• QSB 4.5, QSB 6.7
  
  

• 6C8.3, 6CT8.3
  
  

• ISC, QSC series engines
  
  

Heat Exchanger and Oil Cooling Gaskets

Heat Exchanger Gasket – 5” Diameter

A durable gasket that seals the connection between the heat exchanger and the 6CTA engine block. It helps isolate coolant from engine oil, ensuring optimal engine temperature regulation.

Oil Cooler Gasket

Ensures a leak-free seal between the oil cooler housing and the engine block. Made from oil-resistant material with steel reinforcement for longevity.

Oil Cooler Cover Gaskets

Two variants are available:

• Outer gasket for the oil cooler cover
  
  

• Inner gasket providing secondary containment
  
  

Both are engineered to maintain proper oil pressure and prevent external leaks.

Fuel System Gaskets

Fuel Transfer Pump Gasket

A small but essential component that seals the mechanical fuel pump to the block. Each pump uses two gaskets—one at the mounting surface and one for the supply port.

Applicable engines:

• 4BT, 6BT, 6CT
  
  

• ISC, QSC
  
  

Gear Housing and Rear Cover Gaskets

Rear Cover Gasket – 6CTA / ISC / QSC Compatible

This gasket seals the rear housing plate that encloses timing gears and crankshaft seals. A proper seal ensures oil retention and gear alignment.

Gear Housing Gasket

Protects against oil leaks in the front gear train housing. Manufactured from a high-strength composite for resistance to torque stress and vibration.

Thermostat Gasket

A simple yet crucial gasket that prevents coolant leaks at the thermostat housing. Proper sealing at this point helps maintain engine temperature and coolant pressure.

Additional Sealants and Compounds

While gaskets provide the primary seal, professional installations often call for supplemental sealants. Diesel Pro Power offers a full line of gasket makers, sealant sprays, and adhesives compatible with Cummins 6CTA engines.

High-Temperature Jointing Compound – Up to 760°C

Ideal for sealing turbocharger and exhaust system flanges, this compound withstands extreme thermal cycles without hardening or cracking.

Gasket Spray – High Tack Sealant

Used to "stick" gaskets during installation and fill micro-imperfections on the mating surfaces. Especially useful for older castings or warped flanges.

Silicone-Based Gasket Makers

• Sensor-Safe RTV (Ultra Blue): For electronic and sensor-mounted areas like valve covers or timing covers
  
  

• High Temp RTV: For turbo systems, manifolds, or oil pans
  
  

• Non-Hardening Pliable Sealant: Flexible for reusable assemblies
  
  

Liquid Gasket Sealants & Threadlockers

• 3H Liquid Gasket Maker: Ideal for oil and coolant sealing without a physical gasket
  
  

• Red Threadlocker: For bolts on high-vibration areas like exhaust brackets or water pumps
  
  

Cold Weld – J-B Weld

For temporary or emergency repairs, J-B Weld provides a durable steel-reinforced epoxy bond, capable of patching cracked housings or stripped bolt holes until proper repair is possible.

Why Choose Diesel Pro Power for Cummins 6CTA Gaskets?

• Engineered Fit: All gaskets and sealants are designed to match Cummins OEM specs for the 6CTA platform.
  
  

• Marine & Industrial Ready: Our products are built to withstand harsh saltwater environments, constant load applications, and extended duty cycles.
  
  

• In Stock & Ready to Ship: Most gaskets are available for immediate dispatch worldwide.
  
  

• Trusted by 40,000+ Customers: Diesel Pro Power has earned a reputation for reliability, quality, and global service in the diesel parts industry.