MotoRad MGC903 Locking Fuel Cap for Flex-Fuel Applications with Black Cam-On (non-threaded) Caps Fuel Tank Cap Fits Chevy Silverado 1500 04–12 2500 HD 04–10 Malibu 04–12 Tahoe 04–13 Impala 06–10

So I've had numerous locking gas caps through the years, not because they break or are unreliable but because I've had numerous vehicles on which I put them. This brings up my first point, please make sure you get the right cap for the right application. Not all fuel filler tubes are the same, nor are the retaining mechanisms the same. I've had good luck with Amazon's fitment check ("Make Sure It Fits!" thing at the top of the page), so I'd start there. If possible, also check the manufacturer's website for a fitment guide and compare the model number to what Amazon shows. Nice to double check.Anyway, This is a fine locking cap. It's traditional in the sense that the key is double-sided and will insert either way to lock/unlock the cap. It also does require two hands to operate, as the top of the cap will spin freely from the base when locked, which is, of course, how these things work. To engage the lock, though, and unlock it, you'll typically need both hands free or be very dextrous with one hand. You have to insert the key to unlock the cap and it is then, thus, trapped in the cap (i.e., you can't pull the key out of the cap) until you lock the cap back. That means you've got to make sure you keep track of it since any other keys on the key ring will generally go with the cap itself as well while you're filling up the tank. Not a big deal, but something to remember. Also, note that the key is coated in a rubberized plastic. This is good in that it's a little grippier than a bare metal key, but bad in that it makes the thickness of the key much greater and, therefore, may not work as well on your key ring. I found it a bit of a pain since it didn't lay flat with the other keys on the keyring in my pocket.I think the mechanism of this one is sound and simple. Should last for years. If the above minor complaints are a concern, then I'd suggest looking into the Stant model locking gas cap. It has a little more sophisticated mechanism that doesn't require the key to lock it back BUT it also doesn't seem to be as durable a mechanism, as the first one I got was broken right out of the box. For simplicity and durability I rate this one as a 4 out of 5. I'm not sure what it would take to get a 5/5 other than, perhaps, better style and/or ease of use (one handed use please?).

working for now, but Quality of product seem to be lacking, seems a bit flimsy.

Great cap just what I needed to secure gas access.

It doesn't always lock & leaves me unsure if it did lock. Not sure if it locks well when it does lock. But, the key mechanism works well, turns both ways & stays unlocked if that's how u want it.

Fit was perfect, no pressure leaks. No idea how tamper resistant is is. Seemed to be the simplest solution instead of the entire locking door.

I'm very happy with it

Does not include a tether cord, and feels kinda cheap, but it seems to get the job done. A good item for the price. So far so good.

Works like a charm

2008 gmc sierra

This locking gas cap fits my car perfectly. Love that Amazon has you tell them what your car is, and then scans to make sure its compatable. A valuable service! The cap does exactly what it claims to do. Very pleased.

Purchased this product as advertised as used. The part didn't look used buy the cap won't lock, you can spin it off without the keys. I suspect somebody returned this product because it wouldn't lock and I purchased it as used. I kept it because it fit good and I needed a gas cap.

Good value at a good price! After reading some other reviews, I was skeptical. Once installed, it is a two handed operation to engage the locking option properly. But it WORKS! No more siphoned gas! After one week of installation with various level of fuel in tank, there was no “Service Engine” light that came on. Very please with this gas cap when compared to buying a new one at the GM dealership.

There is no physical locking mechanism to prevent the cap from turning and being removed. The lock feature seems to just control the internal spinning mechanism. Not sure which way to turn the key to "lock" it, but in either position it is easy to remove the cap; although in one position it does take a few extra turns to remove it. Maybe it works better on other vehicles that provide a better fit, but I did use their system to confirm that it would fit my model before ordering. Cap was the right size and did generally fit, but doesn't lock which was the whole point of a locking cap. Don't order this product.