Cummins 4BT Engine Parts - Gasket Section

Cummins 4BT Gaskets & Gasket Sets

Diesel Pro Power offers one of the most complete selections of Cummins 4BT engine gaskets, seals, and gasket maker solutions available anywhere online. From full upper and lower gasket sets to specialty seals for the thermostat, oil cooler, turbo, or push rod cover, every component is built to meet or exceed OEM standards. Whether you’re rebuilding a 4BT from the bottom up or performing routine maintenance on your marine or industrial Cummins 3.9L engine, having the correct gaskets is critical to prevent leaks, ensure proper combustion, and protect your engine investment.

With over 40,000 satisfied customers, Diesel Pro Power is the trusted source for high-performance, precision-fit Cummins 4BT gaskets worldwide.

Full Gasket Sets for the Cummins 4BT Engine

Upper Gasket Sets (Standard and Oversize)

The upper gasket set includes all the essential seals needed for the cylinder head, intake, and exhaust manifolds. It’s typically used when replacing or servicing the head gasket, valve cover, or turbo components.

We offer both:

• Standard Upper Gasket Sets, ideal for routine top-end repairs or rebuilds.

• Oversize Upper Gasket Sets (0.25 mm) for engines that have been resurfaced or decked, ensuring a perfect fit and seal.

Upper sets typically include:

• Head gasket

• Intake manifold gasket

• Exhaust manifold gasket

• Valve cover gasket

• Turbocharger oil gaskets

• Thermostat housing gasket

• Injector seal rings

• Push rod cover gasket

Lower Gasket Sets

The lower gasket set covers everything below the cylinder head and is used when overhauling the crankcase, replacing the oil pan, or resealing the block. A lower set often includes:

• Oil pan gasket

• Front and rear crankshaft seals

• Water pump mounting gasket

• Oil cooler gaskets

• Fuel pump gaskets

• Rear gear housing seals

• Camshaft thrust plate gasket

Individual Gaskets for Common 4BT Repairs

Cummins 4BT Head Gasket

The head gasket is one of the most critical sealing components in the Cummins 4BT. It provides a high-pressure seal between the engine block and cylinder head. Our premium-quality 4BT head gaskets are compatible with both the naturally aspirated 4B and the turbocharged 4BT 3.9 engines. Each head gasket is designed for precise compression sealing to prevent coolant leaks, oil seepage, and combustion blow-by.

Exhaust Manifold Gasket

The exhaust manifold gasket ensures a tight seal between the cylinder head and the exhaust manifold, preventing hot gases from escaping. This helps maintain turbo boost efficiency (if equipped) and ensures proper exhaust flow out of the engine. Perfect for both marine and stationary applications where durability under heat stress is essential.

Intake Manifold Gasket

The intake manifold gasket plays a vital role in keeping air from leaking between the intake manifold and the head. Any failure here leads to performance issues, poor fuel economy, and potential damage. Our gaskets are constructed with heat-resistant materials and a factory-style design for a perfect seal every time.

Marine-Specific Gaskets

Raw Water Pump Mounting Gasket

If you're running a 4BT in a marine application, sealing the raw water pump correctly is critical. This specialized gasket to mount the saltwater pump ensures reliable operation and corrosion resistance in harsh marine environments. Prevents coolant leaks and contamination from saltwater exposure.

Heat Exchanger O-Ring Seal

This O-ring gasket is used in Cummins marine heat exchanger systems and provides an essential watertight seal between the heat exchanger and mounting surfaces. Each engine typically uses two per system, and we recommend replacement during any coolant system service.

Aftercooler O-Ring

Sealing the aftercooler in a turbocharged marine 4BT engine is vital for maintaining correct air temperatures and preventing moisture intrusion. This aftercooler O-ring provides an airtight seal and resists chemical degradation from salt-laden air and marine fuel vapors.

Engine Accessory Gaskets

Valve Cover Gasket

The valve cover gasket helps prevent oil from seeping out of the top of the cylinder head. It’s a common replacement during regular valve lash adjustments or cylinder head service. Our high-temp gaskets resist oil degradation and fit snugly into the valve cover groove.

Push Rod Cover Gasket

Located on the side of the block, the push rod cover gasket seals the access panel for the valve train and push rods. This gasket is often overlooked but is a common source of oil leaks if worn. Ours are precision-molded and durable even in high-vibration engine compartments.

Fuel Injection Pump Gasket

This injection pump gasket ensures proper sealing between the fuel pump and the gear housing, preventing both oil and fuel leaks. Designed to handle high pressures and compatible with diesel fuel exposure.

Fuel Transfer Pump Gasket

Our fuel transfer pump gasket helps seal the mechanical fuel pump to the engine block and must be replaced if the pump is removed or serviced. Two gaskets are typically used per pump, and installation is straightforward with a clean mating surface.

Cooling System Gaskets

Oil Cooler Core Gasket

The oil cooler gasket maintains separation between oil and coolant in the heat exchanger core. A failure here can lead to fluid contamination—replacing this gasket is essential during any oil cooler service.

Water Pump Seal Ring

This seal ring is used between the coolant housing and water pump. It is small but critical for leak-free water pump operation.

Thermostat Seal and Housing Gasket

The thermostat housing gasket and thermostat seal are used when replacing or servicing the thermostat. These parts ensure correct temperature control and seal the coolant passages, preventing leaks in both marine and land-based engines.

Oil System Gaskets

Oil Pan Gasket

One of the most commonly replaced gaskets, the oil pan gasket ensures a tight seal along the bottom of the crankcase. Our gasket is oil-resistant and built to maintain a seal even after thousands of hours of engine vibration.

Turbo Oil Drain Gasket

Used in turbocharged 4BT engines, this gasket seals the return line from the turbo to the oil pan. Preventing leaks here is critical to ensure oil circulation and turbo longevity.

Filter and Housing Gaskets

Filter Head Gasket

The filter head gasket helps seal the base of the oil filter head. This component should be replaced anytime the housing is removed or serviced to avoid pressure loss or leaks.

Cover Plate Gasket

Used on various access covers throughout the Cummins 4BT engine, this gasket for cover plates fits areas such as gear housings or auxiliary mounting flanges.

Gasket Maker Products & Sealants for Cummins Engines

When working with cut gaskets, older housings, or custom modifications, gasket makers and sealants can be vital tools to ensure a leak-free installation. Diesel Pro Power offers a complete lineup of high-quality sealants for your 4BT engine:

Gasket Makers & RTV Sealants

• High-Temp RTV Silicone Gasket Maker
  Withstands extreme temperatures, ideal for turbo flanges, exhaust joints, and thermostat housings.

• Ultra Blue RTV – Sensor Safe
  Perfect for electronic engine setups. Safe on oxygen sensors and other sensitive components.

• Non-Hardening Pliable Sealant
  Great for surfaces that may need to be reopened or adjusted later. Doesn’t crack or dry out.

• Silicone Sensor Safe Blue RTV
  Widely used for timing covers, valve covers, and water pumps.

High-Tack and Threadlocker Products

• High Tack Gasket Spray Sealant
  Used to hold cut gaskets in place during assembly and seal imperfections in old or pitted metal.

• Threadlocker Red (High Strength)
  Recommended for high-vibration environments. Secures bolts and prevents loosening over time.

• Cold Weld (J-B Weld)
  Ideal for emergency repairs or sealing minor cracks in the block or components.

Choosing the Right Gasket or Seal for Your 4BT

Selecting the correct gasket comes down to understanding the location, material compatibility, and purpose of the seal. Some key considerations include:

• Application Environment: Marine engines face salt exposure; land-based engines may face high dust or vibration.

• Temperature Resistance: Components like turbo flanges require high-temp materials.

• Fuel/Oil Compatibility: Gaskets exposed to diesel fuel or lubricants must resist chemical breakdown.

• Service Frequency: Areas that need regular inspection (e.g., valve cover) benefit from reusable or pliable gaskets.

We recommend replacing gaskets any time their associated component is removed. Never reuse old or compressed gaskets, especially for critical components like the head or turbocharger.

Why Buy Gaskets for Cummins 4BT from Diesel Pro Power?

• Wide Compatibility: Designed for 4B, 4BT, and 4BTA variants.

• Marine & Industrial Ready: Built for durability under harsh use.

• OEM Quality: Every gasket meets or exceeds Cummins factory specifications.

• Fast Shipping: Worldwide delivery with most items in stock and ready to ship.

• Dedicated Support: Our expert team helps identify the exact gasket or seal you need.