John Deere OEM Gas Cap - GX22166,1

What It Is

This is an OEM replacement gas cap (part number GX22166) for select John Deere lawn tractors, zero-turn mowers, and utility vehicles. It seals the fuel tank to prevent leaks, debris ingress, and fuel evaporation during operation and storage.

Fitment & Compatibility

• Direct fit for John Deere models using the GX22166 cap, including popular series like X300, X500, X700, Z900, and certain Gator utility vehicles.
• Measure the tank opening: The cap fits a standard 1.5-inch (38mm) threaded fuel neck. If your tank has a larger or smaller opening, this cap won’t work.
• Check your model number: Verify compatibility using your machine’s serial number or by looking up the GX22166 in the official John Deere parts catalog.
• OEM vs aftermarket: This is genuine John Deere—same as the original. Aftermarket caps may fit but often have cheaper plastic or looser seals.
• Deck size doesn’t matter—only the fuel tank neck diameter and thread pattern.

Key Things to Know

• Installation is trivial: Unscrew the old cap, screw on the new one hand-tight. No tools needed.
• The cap is vented—it allows air in to prevent vacuum lock but keeps fuel from sloshing out. If your mower stalls or runs rough, the vent could be clogged (replace cap).
• Common gotcha: Some aftermarket caps lack a tether or retention strap—this OEM cap includes one to prevent loss.
• Quality note: The plastic can become brittle over time, especially if exposed to sun or ethanol fuels. Expect 2-3 years of typical use before replacement.

Should You Buy It

Buy it if your original cap is cracked, leaking, missing, or causing a vapor lock issue. It’s a cheap, direct-fit fix for most John Deere riders and zero-turns. Skip it if you have an older model with a non-standard fuel neck (measure first) or if you prefer a metal cap for durability.