Frequently Asked Questions About Kenworth T680 Fuel Tank Caps

Will these fuel tank caps fit my specific year model Kenworth T680?

Most aftermarket fuel tank caps for the Kenworth T680 are designed to fit model years 2013 through current production models. However, there can be variations based on your specific tank configuration. Standard 4-inch and 5-inch neck openings are the most common sizes. We recommend checking your existing cap diameter or contacting our customer service team with your VIN to ensure proper fitment before ordering.

What's the difference between locking and non-locking fuel caps, and which should I choose?

Locking fuel caps feature a key mechanism that prevents unauthorized access to your fuel tank, providing security against fuel theft and tampering. Non-locking caps offer quicker access for frequent refueling but lack theft protection. If you frequently park in unsecured areas or have experienced fuel theft, we strongly recommend locking caps. For owner-operators who primarily use secure facilities, non-locking caps may be sufficient and more convenient.

Are chrome-plated fuel caps worth the extra cost compared to standard aluminum?

Chrome-plated fuel caps offer superior corrosion resistance and maintain their appearance longer than standard aluminum, especially in harsh weather conditions or areas with road salt exposure. While aluminum caps are lighter and less expensive, they may show oxidation and wear more quickly. Chrome caps typically last 3-5 years longer and are ideal if you want to maintain a polished, professional appearance for your T680.

How difficult is it to install a replacement fuel cap, and what should I watch out for?

Installing a replacement fuel cap is typically a straightforward 5-minute job requiring no special tools. Simply unscrew the old cap counterclockwise and thread the new one clockwise until it seats firmly. The main concern is ensuring you don't cross-thread the cap, which can damage both the cap and tank neck. Start threading slowly and back off if you feel resistance. Also, check that the rubber gasket is properly seated in the cap before installation to prevent fuel vapors from escaping.

Why is my new fuel cap causing a check engine light or emissions warning?

Modern Kenworth T680s have evaporative emission (EVAP) systems that monitor fuel tank pressure. An incompatible or improperly sealed fuel cap can trigger warning lights. Ensure you're using an OEM-spec cap rated for your truck's emission system requirements. If the light appears after installation, first check that the cap is fully tightened (usually 3-4 clicks past initial resistance). If the problem persists, the cap's pressure relief valve may not match your system's specifications, and you should verify compatibility with your specific engine and emission year.