Peterbilt 567/579 Fuel Tank Caps

Frequently Asked Questions About Peterbilt 567/579 Fuel Tank Caps

Will this fuel tank cap fit my Peterbilt 567 or 579 without modification?

Fuel tank caps in this category are designed to match the fuel tank neck diameter and thread pattern used on Peterbilt 567 and 579 models. However, fuel tank sizes and neck styles can vary depending on the truck's build date and configuration, so it's important to check your existing cap's diameter and thread type before ordering to ensure a proper fit.

Are these caps vented or non-vented, and does it matter which one I choose?

Fuel tank caps typically come in either vented or non-vented styles. Vented caps allow air to enter the tank as fuel is drawn out, which helps maintain proper fuel flow, while non-vented caps are sealed. Using the wrong type for your fuel system can cause performance issues such as fuel starvation or pressure buildup, so it's best to match the replacement cap to the style originally installed on your truck.

What material and finish options are available for these caps?

Most fuel tank caps in this category are made from durable materials such as steel, aluminum, or chrome-plated metal to withstand daily exposure to weather, road debris, and fuel. Chrome and polished finishes are popular for adding a finished look to the tank area, while painted or plain metal options offer a more functional appearance at a lower cost.

How do I know if I need a locking fuel tank cap?

A locking fuel tank cap is a good option if fuel theft or tampering is a concern, especially for trucks that are parked in shared lots or travel long routes. Locking caps require a key to remove, adding a layer of security compared to standard twist-on caps. If security isn't a priority, a standard non-locking cap will work just as effectively for daily use.

Is installation straightforward, or will I need special tools?

In most cases, replacing a fuel tank cap is a simple task that only requires removing the old cap and threading on the new one by hand, similar to a car's gas cap. No special tools are typically needed. If you're installing a locking cap, make sure to test the key and locking mechanism before hitting the road to confirm it operates smoothly.