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Engine Parts

Explore a diverse range of new semi-truck engine parts at 4 State Trucks. Discover quality OE and aftermarket replacement filters, belts, sensors, flywheel components, and more online to ensure your engine runs smoothly. Elevate your truck's engine with our quality parts today!
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  • 4 Spade Engine Brake Switch Replaces K301-270, D66053216 For Kenworth T300-T450

    4 Spade Engine Brake Switch Replaces K301-270, D66053216 For Kenworth T300-T450

    AUTOMANN USA

    $29.93
    Engine Brake Switch For Kenworth T300 & T450 Replaces 8956K790Engine braking safety starts with accurate switch performance, and this 4 Spade Engine Brake Switch for Kenworth T300-T450 trucks is...
    02-16190604
    SKU:
    02-16190604
    Truck Class:
    Heavy Duty
    Make:
    Kenworth
    Product Type:
    Lighting
    Ready To Ship:
    Yes
    $29.93
    Qty in Cart: 0
    Price:
    $29.93
    Subtotal:
  • FREE SHIPPING OVER $249
    Cab Air Pre-Filter For Kenworth T800, W900B & W900

    Cab Air Pre-Filter For Kenworth T800, W900B & W900

    FREEDOM AIR FILTERS

    $36.99
    1986-2018 Fresh Air Filter Pre-Filter Fits Kenworth* High Quality Polyester And ABS Plastic Pre-Filter * 4 Mounting Screws Included* Color Black* UV Resistant* Sold Individually* Warranty On...
    02-091306
    SKU:
    02-091306
    Truck Class:
    Heavy Duty
    Material Options:
    Plastic/Poly
    Make:
    Kenworth
    Product Type:
    Exterior
    Ready To Ship:
    Yes
    $36.99
    Qty in Cart: 0
    Price:
    $36.99
    Subtotal:
  • Stainless Steel Power Steering Reservoir Cover For Kenworth

    Stainless Steel Power Steering Reservoir Cover For Kenworth

    TWELVE GAUGE

    $222.99
    16 Gauge Stainless Steel Power Steering Reservoir CoverDo you need a power steering reservoir cover for your Kenworth Truck? This high quality power steering reservoir cover is very simple to...
    02-071400001
    SKU:
    02-071400001
    Truck Class:
    Heavy Duty
    Material Options:
    Stainless Steel
    Make:
    Kenworth
    Product Type:
    Engine Parts
    Size Options:
    16 Gauge
    Height Options:
    7 Inch
    Diameter Options:
    7 Inch
    $222.99
    Qty in Cart: 0
    Price:
    $222.99
    Subtotal:
  • FREE SHIPPING OVER $249
    Front Motor Mount Bushing For Kenworth T600, T660, T680, W900 With CAT Engine

    Front Motor Mount Bushing For Kenworth T600, T660, T680, W900 With CAT Engine

    AUTOMANN USA

    $31.85
    Front Motor Mount BushingsRestore proper engine support and reduce unwanted vibration with this front motor mount bushing designed for Kenworth T600, T660, T680, and W900 trucks equipped with CAT...
    02-07040001
    SKU:
    02-07040001
    Truck Class:
    Heavy Duty
    Make:
    Kenworth
    Product Type:
    Engine Parts
    Style Options:
    Caterpillar
    Material Options:
    Rubber
    Ready To Ship:
    Yes
    $31.85
    Qty in Cart: 0
    Price:
    $31.85
    Subtotal:
  • BESTfit 7.875 X 8 X 2 Inch Heater Core Replaces 108263 For Kenworth T600, T800 & W900L/B/S

    BESTfit 7.875 X 8 X 2 Inch Heater Core Replaces 108263 For Kenworth T600, T800 & W900L/B/S

    BESTFIT TRUCK PARTS

    $192.99
    BESTfit Heater Core With 5/8 Inch Inlet/Outlet Fits Kenworth T600, T800 & W900Keep your cab heating system performing efficiently with the BESTfit 7.875 x 8 x 2 Inch Heater Core, designed to replace...
    02-070000019
    SKU:
    02-070000019
    Truck Class:
    Heavy Duty
    Make:
    Kenworth
    Product Type:
    Engine Parts
    Height Options:
    7 1/2 Inch
    Length Options:
    2 Inch
    Width Options:
    8 Inch
    $192.99
    Qty in Cart: 0
    Price:
    $192.99
    Subtotal:
  • BESTfit Red Poly Motor Mount Bushings W/ Steel Sleeve-Replaces 05-08968 For Peterbilt 359, 377, 378, 379

    BESTfit Red Poly Motor Mount Bushings W/ Steel Sleeve-Replaces 05-08968 For Peterbilt 359, 377, 378, 379

    BESTFIT TRUCK PARTS

    $17.33
    BESTfit One Position Poly Motor Mount Bushings With Steel SleeveThis high quality one position motor mount bushings with steel sleeve is made with a high quality red polyurethane. This bushing is...
    01-12412
    SKU:
    01-12412
    Truck Class:
    Heavy Duty
    Material Options:
    Plastic/Poly
    Make:
    Peterbilt
    Product Type:
    Engine Parts
    Color:
    Red
    Ready To Ship:
    Yes
    $17.33
    Qty in Cart: 0
    Price:
    $17.33
    Subtotal:
  • Chrome Engine Heater Plug Socket For Peterbilt 389

    Chrome Engine Heater Plug Socket For Peterbilt 389

    OPP - ORIGINAL PARTS PROGRAM

    $98.93
    Chrome Engine Heater Plug Socket - Socket OnlyEnhance your Peterbilt 389's engine performance and cold-weather reliability with this Chrome Engine Heater Plug Socket. Designed for durability and...
    01-072200
    SKU:
    01-072200
    Truck Class:
    Heavy Duty
    Location:
    Made In USA
    Material Options:
    Aluminum
    Make:
    Peterbilt
    Product Type:
    Engine Parts
    $98.93
    Qty in Cart: 0
    Price:
    $98.93
    Subtotal:
  • Power Steering Reservoir Base & Bracket For 575.1028 For Peterbilt 300 Series

    Power Steering Reservoir Base & Bracket For 575.1028 For Peterbilt 300 Series

    AFTERMARKET

    $250.99
    Power Steering Reservoir Base & BracketSecurely mount your power steering reservoir with this quality base and bracket. For ease of use, it features pre-cut 0.687 inch mounting holes that are 3.125...
    01-0714004
    SKU:
    01-0714004
    Truck Class:
    Heavy Duty
    Make:
    Peterbilt
    Product Type:
    Engine Parts
    Color:
    Black
    Finish Options:
    Black Powder Coat
    Material Options:
    Steel
    $250.99
    Qty in Cart: 0
    Price:
    $250.99
    Subtotal:
  • Power Steering Reservoir Base & Bracket For 575.1027 For Peterbilt 300 Series

    Power Steering Reservoir Base & Bracket For 575.1027 For Peterbilt 300 Series

    AFTERMARKET

    $188.99
    Power Steering Reservoir Base & BracketSecurely mount your power steering reservoir with this quality base and bracket. For ease of use, it features pre-cut 0.687 inch mounting holes that are 3.125...
    01-0714002
    SKU:
    01-0714002
    Truck Class:
    Heavy Duty
    Make:
    Peterbilt
    Product Type:
    Engine Parts
    Material Options:
    Steel
    Color:
    Black
    Finish Options:
    Black Powder Coat
    $188.99
    Qty in Cart: 0
    Price:
    $188.99
    Subtotal:
  • FREE SHIPPING OVER $249
    Power Steering Reservoir Base Bracket For Peterbilt 386

    Power Steering Reservoir Base Bracket For Peterbilt 386

    AUTOMANN USA

    $172.99
    Replacement Base Bracket For Power Steering ReservoirEnsure your truck's power steering system stays secure with the Power Steering Reservoir Base Bracket. This durable bracket provides a reliable...
    01-07100002
    SKU:
    01-07100002
    Truck Class:
    Heavy Duty
    Make:
    Peterbilt
    Product Type:
    Engine Parts
    Color:
    Black
    Finish Options:
    Black Powder Coat
    Material Options:
    Steel
    $172.99
    Qty in Cart: 0
    Price:
    $172.99
    Subtotal:
  • Peterbilt 359 AC Grilldenser By BESTfit

    Peterbilt 359 AC Grilldenser By BESTfit

    BESTFIT TRUCK PARTS

    $824.99
    BESTfit AC Grilldenser Fits Peterbilt 359 1979-1986This BESTfit AC Grilldenser is a perfect match for Peterbilt 359 models from 1979 through to 1986. With measurements set at 26.00 inches in height,...
    01-070031
    SKU:
    01-070031
    Truck Class:
    Heavy Duty
    Make:
    Peterbilt
    Product Type:
    Engine Parts
    $824.99
    Qty in Cart: 0
    Price:
    $824.99
    Subtotal:
  • Peterbilt 330, 357, 379, 385 2 Pin Low Pressure Switch Normally Open Replaces 18-03834, P93CAA3604-1, 18-04331 By BESTfit

    Peterbilt 330, 357, 379, 385 2 Pin Low Pressure Switch Normally Open Replaces 18-03834, P93CAA3604-1, 18-04331 By BESTfit

    BESTFIT TRUCK PARTS

    $29.99
    BESTfit Low Pressure Switch With Metric Fitting Style, Close 47 PSI & Open 23 PSIMaintain optimal performance and safety in your truck's air conditioning system with the BESTfit 2 Pin Low Pressure...
    01-070000024
    SKU:
    01-070000024
    Truck Class:
    Heavy Duty
    Make:
    Peterbilt
    Product Type:
    Engine Parts
    Ready To Ship:
    Yes
    $29.99
    Qty in Cart: 0
    Price:
    $29.99
    Subtotal:
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Shop Semi Truck Engine Parts

Your truck’s engine is the heart of your business. When it’s running right, you’re making money. When it’s not, you’re losing time and profits. That’s why 4 State Trucks offers the semi truck engine parts you need to keep your rig on the road and working hard. We stock the critical components that solve real problems for real drivers. Whether you’re fighting diesel fuel system issues, truck engine cooling problems, or just normal wear and tear, the right replacement parts can mean the difference between staying ahead—or getting left behind.
- Boost performance and efficiency: Upgrading worn components helps your engine breathe better, burn cleaner, and run stronger.
- Protect your investment: Durable parts cut down on wear, extend engine life, and help you avoid expensive breakdowns.
- Save time and money: Easy-to-install designs mean faster repairs and less time off the road.
- Stay ready for every mile: Quality parts give you the confidence to tackle tough loads, long hauls, and everything in between. It’s not just about replacement—it’s about protecting your truck, your schedule, and your bottom line.

Best Features of Our Heavy Duty Truck Engine Parts


- Built tough for heavy-duty commercial use.
- Fits a wide range of semi truck makes and models.
- Helps cut downtime and avoid major repairs.
- Fast shipping and expert support when you need it.

Shop Diesel Engine Truck Parts at 4 State Trucks

Stay ahead of engine problems before they cost you. Shop at 4 State Trucks today and keep your semi-truck’s engine, fuel, and even exhaust system running at prime capacity.

Frequently Asked Questions About Semi-Truck Engine Parts

What engine parts are compatible with my specific truck model and year?

Engine part compatibility varies significantly between truck manufacturers, models, and production years. For accurate fitment, you'll need your engine serial number and model information (found on the engine data plate), along with your truck's OEM. Common engine models include Caterpillar C15/C13, Cummins ISX/N14, Detroit DD15/Series 60, and Paccar MX-13. Always cross-reference part numbers with your engine's service manual or contact our technical support team with your specific engine details to ensure proper fitment.

How difficult is it to install engine components like water pumps, turbochargers, or EGR valves?

Installation difficulty varies by component and your mechanical experience. Basic items like air filters, belts, and thermostats typically require standard tools and 30-60 minutes. Complex components like turbochargers, EGR valves, or fuel injectors often require specialized tools, diagnostic equipment, and 2-8 hours of labor. Many drivers handle oil coolers, water pumps, and sensors themselves with proper service manuals. For critical components affecting emissions or requiring ECM programming, professional installation is recommended to maintain warranties and ensure proper operation.

What's the difference between OEM and aftermarket engine parts in terms of quality and longevity?

OEM parts are manufactured to original equipment specifications and typically offer the longest service life and exact fit. Quality aftermarket parts from reputable manufacturers like Dorman, PAI, or Interstate-McBee often match OEM performance at 20-40% lower cost. Premium aftermarket parts usually carry 1-2 year warranties compared to OEM's 2-3 years. Budget aftermarket options may save 50-70% but often have shorter lifespans and limited warranties. For critical components like injectors or turbochargers, OEM or premium aftermarket is recommended. For maintenance items like filters, gaskets, and hoses, quality aftermarket parts provide excellent value.

Which engine parts should I keep as spares to avoid roadside breakdowns?

Essential spare parts include serpentine belts, coolant hoses (especially the lower radiator hose), thermostats, fuel filters, and a complete set of sensors (coolant temp, oil pressure, boost pressure). Many drivers also carry a spare water pump, alternator, and starter due to their failure frequency. For emissions-equipped trucks (2007+), there may be a spare EGR valve gasket and DPF pressure sensors can prevent costly downtime. Keep manufacturer-specific items like turbo boost hoses and intercooler boots that aren't readily available at general parts stores. Total investment for a basic spare parts kit typically runs $500-1500.

How can I tell if an engine part is failing before it causes major damage?

Early warning signs vary by component. Water pumps show coolant leaks, wobbling pulleys, or grinding noises. Turbochargers exhibit excessive smoke, oil consumption, or whistling sounds. Injectors cause rough idle, white/black smoke, or poor fuel economy. EGR valves trigger check engine lights, rough running, or excessive soot buildup. Oil coolers show oil in coolant or dropping oil pressure. Regular oil analysis (every 15,000 miles) can detect bearing wear, coolant intrusion, or fuel dilution before catastrophic failure. Installing aftermarket gauges for boost pressure, EGT, and oil temperature provides real-time monitoring of engine health.


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