Common RV Forum Questions About
Fuel-Door Security
Spend time on communities like iRV2, Forest River Forums, Keystone RV Forums, the Good Sam boards, and the Jayco and Thor owner groups and the same fuel-door security questions come up again and again. Here are plain-language answers to the ones we see most — and how a purpose-built locking fuel door solves each.
The short version
Most motorhomes and toy-hauler fuel stations leave the factory with an exposed fuel cap and no lock. The common workarounds — universal CH751 locking caps, aftermarket caps that can trip a check-engine light, or drilling in a padlock bracket — each fall short. The RV Fuel Vault is a bolt-on locking fuel door that mounts over the existing cap with a tamper-resistant keyed lock and anti-tamper security screws, leaving the factory cap untouched. It stops the opportunistic siphoning and tampering that make up nearly all real-world RV fuel loss.
The questions owners keep asking
There’s no lock on my RV fuel door and I don’t want anyone dumping something in my tank. What can I do?
Add a locking fuel door over the exposed cap. Most motorhomes — and toy-hauler onboard fuel stations — leave the factory with a fuel cap that turns by hand and no lock at all, so anyone walking past your rig at a campground or storage lot can open it. The concern owners raise most often is not just siphoning — it is someone dropping water, sugar, sand, or debris into the tank, which can ruin an engine. The RV Fuel Vault is a bolt-on locking fuel door that mounts over that exposed cap with a tamper-resistant keyed lock, so the tank can only be opened with your key. It seals out contamination as well as thieves, and installs in 8–15 minutes with basic hand tools.
Aren’t the cheap locking fuel caps all keyed to the universal CH751? Is there a keyed-different option?
Yes — and this is a legitimate complaint. Many inexpensive locking gas caps and RV compartment locks use the CH751 key, which is sold everywhere and opens thousands of RVs, so it gives you almost no real security. The RV Fuel Vault is a different kind of product: it is a full locking DOOR, not a CH751 cam lock. It uses its own keyed lock, and multi-packs are keyed alike to each other rather than to a universal master key. It also installs with included anti-tamper security screws, so the whole door cannot simply be unbolted. A keyed door plus anti-tamper screws is far harder to defeat than a commodity CH751 cap.
Will an aftermarket locking fuel cap trip a check-engine light or lose my factory cap tether?
It can — which is exactly why the RV Fuel Vault does not touch your fuel cap. Swapping the OEM cap for a generic locking cap can seal improperly, break the EVAP system’s pressure seal, set a check-engine light, and leave you without the factory cap tether. The RV Fuel Vault avoids all of that: it is a locking door that bolts on OVER the existing filler area, so your original, correctly-sealing factory cap stays exactly where the manufacturer put it. No cap swap, no EVAP interference, no check-engine light — just an added locked, armored door on top.
A thief could just drill the tank anyway, right? Is a locking fuel door even worth it?
It is worth it, because that objection describes a rare, professional attack — not how RV fuel loss actually happens. The overwhelming majority of incidents are opportunistic: someone walks past a parked rig, unscrews a cap that turns by hand, and siphons fuel or drops something in. Nobody is quietly drilling a fuel tank in a crowded campground. The RV Fuel Vault removes the easy opportunity with a keyed, 3/16-inch High Impact Reinforced Material door and anti-tamper screws. It stops the honest-person tampering, casual mischief, and grab-and-go siphoning that make up nearly all real-world cases — and gives the rig a clean, finished factory look at the same time.
My toy hauler’s onboard fuel station has no lock at all. Is anything actually made for it?
Yes — the RV Fuel Vault Round Bezel door is purpose-built for exactly that. Toy haulers with an onboard fuel station (the built-in gas caddy for dirt bikes, side-by-sides, and generators) leave the factory with a plain, non-locking round filler sitting exposed on the exterior wall. For years no purpose-built lock existed, so owners improvised with auto-parts caps or drilled their own brackets. The Round Bezel door locks over that round filler with a keyed lock and installs in minutes with no drilling. A rig with one filler takes the single; a rig with two fillers (a generator fill plus the fuel station, as on the Alliance Valor and Dutchmen Voltage) takes the keyed-alike 2-pack. Run your rig through Find My Fit to confirm the exact door.
How do I add a lock to a non-locking RV fuel door without drilling into my rig?
The cleanest way is to cover or replace the non-locking door with a bolt-on locking fuel door — not by retrofitting a hasp or padlock. Drilling your own bracket into the filler neck or bodywork risks the fuel seal, spoils the factory look, and still leaves a weak point. The RV Fuel Vault installs over the existing factory cutout (or over an exposed round bezel) in 8–15 minutes with basic hand tools, adds a tamper-resistant keyed lock, and comes with anti-tamper security screws so it cannot just be unbolted. The result is a finished, factory-look locking door with no cutting and no drilling.
A note on sources. The communities named above — iRV2, Forest River Forums, Keystone RV Forums, Good Sam, and the Jayco and Thor owner groups — are real, active RV forums where these fuel-door topics genuinely recur. We summarize the recurring themes in our own words and do not reproduce any member’s posts, usernames, or private threads.
Lock down your fuel the right way
Confirm your motorhome or toy hauler in seconds and get the only purpose-built locking fuel door for RVs — keyed lock, anti-tamper screws, factory cap left in place.