Frequently Asked Questions About International DuraStar Fuel Tank Caps

Will these fuel caps fit my specific year International DuraStar model?

Our International DuraStar fuel caps are designed to fit models from 2002 to present. However, there are variations between pre-2007 and post-2007 models due to emissions changes. Pre-2007 models typically use a non-locking vented cap with a 2.75" opening, while 2008 and newer models often require a locking cap with integrated pressure relief. Always check your existing cap's part number or measure the tank opening diameter to ensure proper fitment.

What's the difference between locking and non-locking fuel caps, and which one do I need?

Locking fuel caps feature a keyed cylinder to prevent fuel theft and tampering, while non-locking caps use a standard twist-on design. Most fleet operators and owner-operators prefer locking caps for security, especially for overnight parking. Both types are available in aluminum and chrome-plated steel. If you're replacing an existing locking cap, you'll need to specify whether you want keyed-alike caps for multiple tanks or individual keys for each cap.

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

This typically occurs when using the wrong type of cap for your emissions system. DuraStar trucks with EPA 2007+ engines require caps with specific pressure ratings (usually 7-9 PSI) to maintain proper tank pressure. Using a non-vented cap on a system requiring venting, or vice versa, will trigger warning lights. Always verify your truck's emissions year and match the cap's pressure rating to your OEM specifications.

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

Check your existing cap for vent holes around the seal area or look for "VENTED" stamped on the cap. Generally, older DuraStar models (pre-2007) use vented caps to prevent vacuum buildup in the tank. Newer models with evaporative emission controls typically use non-vented caps as the tank venting is handled by the EVAP system. Using the wrong type can cause fuel pump issues, slow filling, or tank deformation.

What's the proper way to install and maintain these fuel caps to prevent leaks?

Before installation, inspect and clean the tank filler neck threads and remove any debris. Apply a thin layer of diesel fuel to the cap's O-ring or gasket for proper sealing. Tighten until you feel firm resistance, then turn an additional 1/4 turn - over-tightening can damage the seal. Replace the O-ring annually or if you notice any cracks, and keep the cap threads clean. For locking caps, lubricate the lock cylinder every 6 months with graphite powder to prevent freezing.