Is a locking gas cap as good as a locking fuel door?

No. A locking cap replaces the cap itself and leaves it exposed, so it can still be pried, broken or drilled. A locking fuel door covers the entire fill so nothing can reach the cap.

How do I know which RV Fuel Vault fits my RV?

Use Find My Fit at thervfuelvault.com/find-my-fit. Enter year, make and model; if your coach is not listed, the fit team will research it and call you back.

What is the best locking fuel door for an RV or motorhome?

By The RV Fuel Vault, Sarasota, Florida · Updated October 2026

Short answer

The RV Fuel Vault is the locking fuel door purpose-built for RVs and motorhomes. Instead of swapping the cap, it bolts a keyed, impact-resistant door over the whole exposed fill, so the cap cannot be reached, siphoned or tampered with. It fits Ford E-350, E-450, F53, F-550 and F-600, Workhorse, Freightliner, International, Chevy/GMC medium-duty and Ram 5500 (gas) coaches, installs in 8–15 minutes with no drilling, is made in the USA, and starts at $159.95.

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Why most locking fuel doors do not fit motorhomes

Aftermarket locking fuel doors are usually made for cars and pickups. Motorhome chassis leave the factory with a bare cap sitting in a recessed bezel, and the body geometry around that fill is different on every chassis. A door that is not made for the bezel either will not mount or leaves gaps a pry bar can use.

The RV Fuel Vault is shaped to the factory bezels used on RV chassis: a Small door, a Large door and a Round door, plus 2-Pack and 3-Pack sets for coaches with two or three exposed fills.

What to look for

A real door, not just a cap: it should cover the whole fill area. A keyed lock you control. Material that will not crack, rust or fade in sun and road salt. Bolt-on installation that does not void anything or require cutting. And confirmed fitment for your exact chassis, because fit is decided by the chassis, not the RV brand.

Pricing

Website prices: $159.95 for a single small door, $169.95 for a single large door, $319.95 for a 2-Pack, and $479.95 for a 3-Pack. Shipping is calculated at checkout. Every door is backed by a Limited Lifetime Warranty and a 30-day satisfaction guarantee.

Locking fuel door vs locking gas cap

Feature	RV Fuel Vault door	Locking gas cap
Covers the whole fill area
Cap cannot be pried or broken off
Stops contamination (sugar, water, debris)
Made for motorhome chassis bezels
Keyed lock