Caterpillar 3304 Diesel Engine Parts
The Caterpillar 3304 is a 7.0_liter, inlineÊ4-cylinder direct_injection diesel engine (425_cu_in) built with a wet_sleeve design and available in both naturally aspirated and turbocharged configurations. Widely appreciated for its mechanical simplicity, rebuildability, and durability, the 3304 delivers dependable power across industrial, construction, marine, and generator applications. Horsepower ranges from approximately 95_HP in naturally aspirated versions to 150Ð170_HP or more in turbocharged models, with torque ratings up to around 420Êlb_ft [oai_citation:0àDiesel Pro](https://dieselpro.com/caterpillar-parts/3304-engines/3304-engine-parts.html?srsltid=AfmBOoqCM0d5mSoFGzZiGXtDGjKZJjKs9vJu7NcgqtXOrGnDQm4NPeI8&utm_source=chatgpt.com) [oai_citation:1à4BT Engines](https://4btengines.com/cat-3304-engine/?srsltid=AfmBOoq9M0hFuBb5j9qexPkTW_GBzRm9k87PM1jNZm6_iAqTo_934hQZ&utm_source=chatgpt.com).
3304 Features
- Inline_4 cylinder layout with a bore of 4.750_in (121_mm) and stroke of 6.000_in (152_mm), displacing Å7.0_L (~425_cu_in) [oai_citation:2àDiesel Pro](https://dieselpro.com/caterpillar-parts/3304-engines/3304-engine-parts.html?srsltid=AfmBOoqCM0d5mSoFGzZiGXtDGjKZJjKs9vJu7NcgqtXOrGnDQm4NPeI8&utm_source=chatgpt.com) [oai_citation:3à4BT Engines](https://4btengines.com/cat-3304-engine/?srsltid=AfmBOoo8EF5HiwM2DKyqafX6Z4-aEOlS4VX9i_RS4osg4IvHL35f0TmP&utm_source=chatgpt.com).
- Direct injection mechanical fuel system designed for reliability and ease of maintenance [oai_citation:4àDiesel Pro](https://dieselpro.com/caterpillar-parts/3304-engines/3304-engine-parts.html?srsltid=AfmBOoqCM0d5mSoFGzZiGXtDGjKZJjKs9vJu7NcgqtXOrGnDQm4NPeI8&utm_source=chatgpt.com).
- Wet-sleeve cylinder liners facilitate in-frame rebuilds and extended service life [oai_citation:5àDiesel Pro](https://dieselpro.com/caterpillar-parts/3304-engines/3304-engine-parts.html?srsltid=AfmBOoqCM0d5mSoFGzZiGXtDGjKZJjKs9vJu7NcgqtXOrGnDQm4NPeI8&utm_source=chatgpt.com).
- Aspiration options: naturally aspirated, turbocharged, or turbo-aftercooled variants offer flexibility based on application needs [oai_citation:6àDiesel Pro](https://dieselpro.com/caterpillar-parts/3304-engines/3304-engine-parts.html?srsltid=AfmBOoqCM0d5mSoFGzZiGXtDGjKZJjKs9vJu7NcgqtXOrGnDQm4NPeI8&utm_source=chatgpt.com).
- Rated horsepower: Å95_HP for NA units, up to 150Ð170_HP for turbocharged versions; marine DIT models can exceed this power range [oai_citation:7àDiesel Pro](https://dieselpro.com/caterpillar-parts/3304-engines/3304-engine-parts.html?srsltid=AfmBOoqCM0d5mSoFGzZiGXtDGjKZJjKs9vJu7NcgqtXOrGnDQm4NPeI8&utm_source=chatgpt.com) [oai_citation:8àDepco Power Systems](https://www.depco.com/marine-engines/caterpillar-3304-dit-marine-engine-item-15321/?utm_source=chatgpt.com).
- Torque output up to ~420_lb_ft (Å560_Nm) around 1,400Ð1,800_RPM [oai_citation:9àDiesel Pro](https://dieselpro.com/caterpillar-parts/3304-engines/3304-engine-parts.html?srsltid=AfmBOoqCM0d5mSoFGzZiGXtDGjKZJjKs9vJu7NcgqtXOrGnDQm4NPeI8&utm_source=chatgpt.com) [oai_citation:10àHeavy Duty Pros](https://www.heavydutypros.com/caterpillar-3304-7-0l-torque-and-engine-specifications.aspx?srsltid=AfmBOoocS62OZ83AGACOhLj8fD6hh_4V3vdHFM0ZM6cMGWe7SygnX3Ot&utm_source=chatgpt.com).
- Weight typically around 1,400Ð1,600_lb dry depending on configuration [oai_citation:11àDiesel Pro](https://dieselpro.com/caterpillar-parts/3304-engines/3304-engine-parts.html?srsltid=AfmBOoqCM0d5mSoFGzZiGXtDGjKZJjKs9vJu7NcgqtXOrGnDQm4NPeI8&utm_source=chatgpt.com).
- Engine design optimized for rebuilds with widespread aftermarket support, making it a popular choice where uptime and repairability are key priorities [oai_citation:12àDiesel Pro](https://dieselpro.com/caterpillar-parts/3304-engines/3304-engine-parts.html?srsltid=AfmBOoqCM0d5mSoFGzZiGXtDGjKZJjKs9vJu7NcgqtXOrGnDQm4NPeI8&utm_source=chatgpt.com) [oai_citation:13àScribd](https://www.scribd.com/document/520974513/cat-3304-3306-industrial-marine-service-manual?utm_source=chatgpt.com).
Common Issues and Replacement Parts Needed
- Wear on fuel injectors or mechanical injection pump components may impact starting, fuel economy, and emissions.
- Turbocharger componentsÑsuch as bearings and sealsÑrequire attention on turbo variants after high hours.
- Please inspect cooling components (water pump, thermostat, hoses) regularly to prevent overheating.
- Oil and coolant leaks from degraded gaskets and seals are common in higher-mileage units.
- Wear items like pistons, liners, rings, bearings, and crankshafts often require replacement during rebuilds.
Key Replacement Parts for the 3304 Engine
Highway & Heavy Parts (HHP), Diesel Pro Power, Maxiforce, and Capital Reman Exchange offer premium-quality parts for CaterpillarÊ3304 engines, including:
- Overhaul kits and cylinder sets (pistons, rings, liners) for naturally aspirated and turbo models
- Crankshaft and connecting rod assemblies, main and rod bearings
- Fuel system components: mechanical injection pumps, calibrated injectors, seals and lines
- Cooling and lubrication parts: water pumps, oil pumps, thermostats, oil coolers
- Turbocharger assemblies, bearings, exhaust manifolds (where applicable)
- Engine rebuild long blocks, timing gear sets, cylinder heads, and valve train components
Major in-frame and full overhaul kits typically range from about $1,200 to $1,600 depending on kit type and supplier [oai_citation:14àHeavy Duty Pros](https://www.heavydutypros.com/caterpillar-3304-7-0l-torque-and-engine-specifications.aspx?srsltid=AfmBOoocS62OZ83AGACOhLj8fD6hh_4V3vdHFM0ZM6cMGWe7SygnX3Ot&utm_source=chatgpt.com) [oai_citation:15àDiesel Pro](https://dieselpro.com/caterpillar-parts/3304-engines/3304-engine-parts.html?srsltid=AfmBOoqCM0d5mSoFGzZiGXtDGjKZJjKs9vJu7NcgqtXOrGnDQm4NPeI8&utm_source=chatgpt.com).
The Caterpillar 3304 remains a highly respected workhorse engine due to its rugged reliability, rebuildable wet_sleeve design, and proven mechanical simplicity. For applications in marine, industrial, construction, and power generation settings, using quality replacement parts ensures continued uptime, consistent performance, and maximum return on engine rebuild investments.
