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Kenworth T300-T450 Fuel Tank Caps

Shop Custom & Aftermarket Kenworth T300-T450 Fuel Tank Caps at 4 State Trucks. We offer a wide array of fuel tank caps, available in locking, non-locking, vented, and non-vented styles to suit your Kenworth gas tanks perfectly.
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  • CSM Black Aluminum Alloy Water Tank Cap

    CSM Black Aluminum Alloy Water Tank Cap

    CHROME SHOP MAFIA

    $16.47
    38MM Water Tank Cap By Chrome Shop MafiaSafeguard your truck's fluids with the Chrome Shop Mafia Black Aluminum Alloy Water Tank Cap. Constructed from heavy-duty aluminum alloy weld billet, it fits...
    09-0707002
    SKU:
    09-0707002
    Ready To Ship:
    Yes
    Color:
    Black
    Make:
    Universal Items
    Product Type:
    Fuel Tanks
    Material Options:
    Aluminum
    $16.47
    Qty in Cart: 0
    Price:
    $16.47
    Subtotal:
  • 4 Inch Aluminum Locking Fuel Cap

    4 Inch Aluminum Locking Fuel Cap

    AFTERMARKET

    $366.99
    4 Inch Fuel Cap Locking-8 NPSF Thread* High Quality Locking Fuel Cap* Aluminum* 4 Inch- 8 NPSF Thread* Vented * Made In USA* Sold Individually* Warranty On Locking Fuel Caps Against Defects In...
    09-06010001
    SKU:
    09-06010001
    Material Options:
    Aluminum
    Product Type:
    Fuel Tanks
    Make:
    Universal Items
    $366.99
    Qty in Cart: 0
    Price:
    $366.99
    Subtotal:
  • Chrome Plastic Fuel Cap Covers For Kenworth

    Chrome Plastic Fuel Cap Covers For Kenworth

    UNITED PACIFIC

    $9.22
    Choose Option(s) to see description.Fitment* Fits Kenworth C500 1972 thru 2024* Fits Kenworth Cabover 1961 thru 2002* Fits Kenworth K100 Cabover 1961 thru 1967* Fits Kenworth K100C 1968 thru 1983*...
    PPR_299099
    SKU:
    PPR_299099
    Product Type:
    Fuel Tanks
    Truck Class:
    Heavy Duty
    Make:
    Kenworth
    Make:
    Peterbilt
    $9.22
    Qty in Cart: 0
    Price:
    $9.22
    Subtotal:
  • Aluminum Leak Defender Fuel Cap and Anti-Siphon Kit For Kenworth

    Aluminum Leak Defender Fuel Cap and Anti-Siphon Kit For Kenworth

    HEAVY TRUCK SOLUTIONS

    $375.99
    Kenworth 3-Piece Leak Defender Fuel Cap and Anti-Siphon KitThe Kenworth Leak Defender Anti-Siphon Kit is a three-piece system with a collar, fuel cap, and anti-siphon tube. It helps fix fuel cap...
    02-06010022
    SKU:
    02-06010022
    Product Type:
    Fuel Tanks
    Truck Class:
    Heavy Duty
    Make:
    Kenworth
    Ready To Ship:
    Yes
    Material Options:
    Aluminum
    $375.99
    Qty in Cart: 0
    Price:
    $375.99
    Subtotal:
  • 3.5 OD X 2.85 Inch ID Fuel Cap Gasket

    3.5 OD X 2.85 Inch ID Fuel Cap Gasket

    AUTOMANN USA

    $3.80
    Replacement 0.14 Inch Thick Fuel Tank Cap GasketNeed a replacement gasket for your 572.1017 fuel cap? This rubber gasket measures 2.85 inches I.D., 3.50 inches O.D., and has a thickness of 0.14...
    09-06010002
    SKU:
    09-06010002
    Truck Class:
    Heavy Duty
    Diameter Options:
    2 3/4 Inch
    Material Options:
    Rubber
    Make:
    Universal Items
    Product Type:
    Fuel Tanks
    Ready To Ship:
    Yes
    $3.80
    Qty in Cart: 0
    Price:
    $3.80
    Subtotal:
  • Locking Fuel Cap Cover For Kenworth, International, Mack, Volvo W/ 3 Inch Thread On Caps

    Locking Fuel Cap Cover For Kenworth, International, Mack, Volvo W/ 3 Inch Thread On Caps

    AFTERMARKET

    $101.99
    Locking Fuel Cap Covers For 3 Inch CapsThis Locking Fuel Cap Cover is the ultimate solution to protect against fuel theft. It locks securely over your existing fuel cap and spins freely when closed...
    29-060324
    SKU:
    29-060324
    Material Options:
    Aluminum
    Truck Class:
    Heavy Duty
    Make:
    Volvo
    Make:
    Kenworth
    Make:
    Mack
    Make:
    International
    Product Type:
    Fuel Tanks
    Ready To Ship:
    Yes
    $101.99
    Qty in Cart: 0
    Price:
    $101.99
    Subtotal:
  • FREE SHIPPING OVER $249
    2 Inch 11.5 TPI Brass Non-Vented Locking Fuel Cap

    2 Inch 11.5 TPI Brass Non-Vented Locking Fuel Cap

    VELVAC

    $79.99
    2 inch Locking Fuel Cap, Non- VentedKeep your fuel tank secure with this 2-inch non-vented brass fuel cap. Locks tight to prevent leaks and tampering. Ideal for various vehicles and equipment. Rest...
    29-060315
    SKU:
    29-060315
    Diameter Options:
    2 Inch
    Truck Class:
    Heavy Duty
    Style Options:
    Non Vented
    Material Options:
    Brass
    Make:
    Universal Items
    Product Type:
    Fuel Tanks
    Ready To Ship:
    Yes
    $79.99
    Qty in Cart: 0
    Price:
    $79.99
    Subtotal:
  • FREE SHIPPING OVER $249
    2 Inch Brass 11.5 TPI Non-Vented Fuel Cap

    2 Inch Brass 11.5 TPI Non-Vented Fuel Cap

    VELVAC

    $45.16
    2 Inch Non-Vented Fuel CapLooking for a reliable fuel cap for your industrial or automotive needs? Check out the Brass 2 Inch 11.5 TPI Non-Vented Fuel Cap. Made of durable brass, it's perfect for...
    09-060301
    SKU:
    09-060301
    Truck Class:
    Universal
    Diameter Options:
    2 Inch
    Material Options:
    Brass
    Make:
    Universal Items
    Product Type:
    Fuel Tanks
    Style Options:
    Non Locking
    Ready To Ship:
    Yes
    $45.16
    Qty in Cart: 0
    Price:
    $45.16
    Subtotal:
  • 2 Inch Aluminum Non-Locking, Female, Vented Fuel Cap With 11-1/2 Threads

    2 Inch Aluminum Non-Locking, Female, Vented Fuel Cap With 11-1/2 Threads

    VELVAC

    $89.99
    2 Inch Non-Locking Fuel Cap, VentedReplace a poorly fitting fuel cap with this premium quality non-locking Velvac Fuel cap that is precision designed to deliver OE fit and functionality. It will...
    09-060300002
    SKU:
    09-060300002
    Truck Class:
    Universal
    Diameter Options:
    2 Inch
    Material Options:
    Aluminum
    Make:
    Universal Items
    Product Type:
    Fuel Tanks
    $89.99
    Qty in Cart: 0
    Price:
    $89.99
    Subtotal:
  • FREE SHIPPING OVER $249
    CSM Non-Vented Lever Lock Flush Fuel Tank Cap Assembly

    CSM Non-Vented Lever Lock Flush Fuel Tank Cap Assembly

    CHROME SHOP MAFIA

    $190.99
    Non-Vented Lever Lock Flush Fuel Cap Assembly by Chrome Shop MafiaThis flush fuel cap assembly features an unvented cap with a lever lock and an O-Ring Seal. It is sold individually and is made in...
    09-060300
    SKU:
    09-060300
    Truck Class:
    Universal
    Location:
    Made In USA
    Style Options:
    Non Vented
    Material Options:
    Aluminum
    Make:
    Universal Items
    Product Type:
    Fuel Tanks
    Ready To Ship:
    Yes
    $190.99
    Qty in Cart: 0
    Price:
    $190.99
    Subtotal:
  • Billet Aluminum Fuel Cap Cover With Ribs For Kenworth

    Billet Aluminum Fuel Cap Cover With Ribs For Kenworth

    LIFETIME NUT COVERS

    $264.99
    Fuel Cap Cover With RibsMake your fuel caps appear new with this pair of covers with ribs. They easily fit on top of the caps securely and come with screws for easy installation. The covers are made...
    02-060310
    SKU:
    02-060310
    Location:
    Made In USA
    Truck Class:
    Heavy Duty
    Material Options:
    Aluminum
    Make:
    Kenworth
    Finish Options:
    Chrome-Plated
    Product Type:
    Fuel Tanks
    Ready To Ship:
    Yes
    $264.99
    Qty in Cart: 0
    Price:
    $264.99
    Subtotal:
  • FREE SHIPPING OVER $249
    BESTfit 3.5 Inch Aluminum Locking Fuel Cap Replaces 572.1036 For Kenworth

    BESTfit 3.5 Inch Aluminum Locking Fuel Cap Replaces 572.1036 For Kenworth

    BESTFIT TRUCK PARTS

    $61.99
    3.5 Inch Fuel Cap- Locking By BESTfitThis locking fuel cap is made of aluminum with a mill finish, and comes with a safety chain and crossbar. It meets the 49 CFR 393.67 requirements for vehicles...
    02-060301
    SKU:
    02-060301
    Truck Class:
    Heavy Duty
    Material Options:
    Aluminum
    Make:
    Kenworth
    Product Type:
    Fuel Tanks
    Ready To Ship:
    Yes
    Finish Options:
    Mill Finish
    Diameter Options:
    3 3/8 Inch
    Style Options:
    Locking
    Location:
    Made In USA
    $61.99
    Qty in Cart: 0
    Price:
    $61.99
    Subtotal:
  • FREE SHIPPING OVER $249
    BESTfit 3.5 Inch Aluminum Vented Non Locking Fuel Cap Replaces A03-12927-4, K071-398 For Kenworth

    BESTfit 3.5 Inch Aluminum Vented Non Locking Fuel Cap Replaces A03-12927-4, K071-398 For Kenworth

    BESTFIT TRUCK PARTS

    $55.99
    3.5 Inch Vented Fuel Cap- Non Locking By BESTfitKeep your Kenworth fuel system protected with the BESTfit 3.5 Inch Aluminum Vented Non-Locking Fuel Cap, designed to replace A03-12927-4 and K071-398...
    02-060300
    SKU:
    02-060300
    Truck Class:
    Heavy Duty
    Material Options:
    Aluminum
    Make:
    Kenworth
    Product Type:
    Fuel Tanks
    Diameter Options:
    3 1/2 Inch
    Ready To Ship:
    Yes
    Style Options:
    Vented
    Location:
    Made In USA
    $55.99
    Qty in Cart: 0
    Price:
    $55.99
    Subtotal:
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Fuel tank caps can offer some added security and a touch of style for your Kenworth T300 or T450? This product lineup has it all'locking, vented, and non-vented options in durable brass, aluminum, or plastic. These caps provide a secure seal to prevent leaks and deter theft while improving fuel efficiency. With various sizes and styles available, you'll find the perfect match to keep your tank secure and your truck looking sharp!

Frequently Asked Questions About Kenworth T300-T450 Fuel Tank Caps

Will this fuel tank cap fit my Kenworth T300, T440, or T470?

Fuel tank caps can vary by tank manufacturer, neck diameter, and locking mechanism even within the same truck model range. Before ordering, check the thread size and diameter of your current cap or the tank fill neck, and compare it to the specifications listed on the product page. If you are unsure, our sales team can help confirm fitment based on your truck's VIN or tank details.

Should I choose a locking or non-locking fuel cap?

Locking fuel caps are a popular upgrade for fleet trucks and owner-operators who park in high-traffic areas, as they help deter fuel theft and tampering. Non-locking caps are simpler and quicker to use but offer no security. Many customers switch to a locking cap after experiencing a theft or siphoning attempt, so consider your parking situation and route history when choosing.

What materials are these fuel tank caps made from, and does it matter?

Fuel tank caps in this category are typically available in chrome-plated steel, stainless steel, or durable plastic/composite construction. Chrome and stainless options tend to hold up better against corrosion and road grime while also matching the polished look of other cab accessories, whereas composite caps are often lighter and more budget-friendly. Choose based on how much exposure to weather and road salt your truck sees, along with your preference for appearance.

How do I know if I need a vented or non-vented fuel cap?

Most modern diesel fuel systems require a vented cap to allow air to enter the tank as fuel is drawn out, preventing a vacuum lock that can starve the engine of fuel. Using the wrong type can cause performance issues or difficulty refueling. If your truck came with a vented cap originally, replace it with the same type; when in doubt, check your Kenworth's service documentation or ask our team before purchasing.

Is installation something I can do myself, or does it require a mechanic?

Replacing a fuel tank cap is generally a simple task that most drivers and owner-operators can handle without a shop visit. In most cases, it is as easy as removing the old cap by unscrewing or unlatching it and threading or securing the new one in its place. If your cap includes a locking mechanism or tether, take a moment to review the included hardware and instructions to ensure it seats and seals properly against the fill neck.


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