The General Motors line of vehicles is pretty extensive. Chevrolet, Cadillac, Pontiac, Buick, GMC, and Oldsmobile all fall under General Motors. With so many makes and models, GM vehicles are very common– and so is a certain key problem.
GM keys remained somewhat unchanged from the 1930s into the 1990s in that they used a single-sided, 6-cut key. These came in slightly different forms, but the specs were all similar. GM finally began to change their key and lock standards in the mid-90s. From then until about 2006, most GM vehicles used a standard double-sided, 10-cut key instead. There is nothing inherently wrong with this key design on the surface, but the problem begins to develop after years of use.
Most locks on the vehicles can be forgiving, but the ignition cylinder is not, due to its design. At some point, many people will begin to experience difficulty getting their ignition to turn, and will have to wiggle and force the key until it cooperates. Sometimes it gets so bad that the vehicle’s operator (or a mechanic who takes a look at it) will decide that the ignition must be bad and needs to be replaced. This results in greater cost and greater headache, with the added problem of no longer having one key to operate the doors and ignition. This process is usually not necessary at all.
When a GM 10-cut key sees years of use, the landings on the key begin to round off and wear away (especially the shallowest ones). On top of that, it is a tip-stop key, which means the key will reach its stopping point in the lock when its tip bottoms out against the back of the lock. Over time, the tip of the key wears back, effectively moving the position of where the cuts land inside the lock. Because the ignition cylinder is not very forgiving, it will have trouble functioning with such a key. The solution? A new key.
No, I’m not talking about a copy. A copy is only as good as the key it was copied from. I’m talking about a fresh key cut to original, factory specs. As locksmiths, we have the ability to generate new keys from scratch. All we have to do to solve your problem is take a look at the key in question, measure it, determine what the original values of the spaces and depths were supposed to be, and cut a fresh key to those specs. 99% of the time, this takes care of the issue cleanly and painlessly. The $25 we charge to do it is money well-spent, compared to what you could be paying for mechanic’s fees and new parts.
This type of key is the most common one to exhibit this problem, but it isn’t the only one. GM vehicles newer than 2006 use a newer type of key, but it still has 10 cuts and it also wears down after time (solving the issue for one of these can sometimes be more costly, however, because this keyway is often used on transponder chip keys). Even the older 6-cut keys sometimes need to be cut fresh, and so do keys from other types of vehicles once in a while. Generally speaking, if you’re having trouble operating your lock, the first thing you should check is the key.
(On a side note, it’s important to mention that some of the wear on both the key and the ignition cylinder can be avoided by not having a heavy keyring. If you commonly drive your vehicle with a key attached to a ring holding 15+ other keys as well as heavy keychains and tags, you will develop problems. Either keep your car keys on a separate, lighter ring, or use a pull-apart keyring when you drive– it will prolong the lifespans of both key and lock.)
One notable exception to the ease of this decode-and-cut solution is the Saturn line. Saturn vehicles often use GM keys and are subject to the same fault caused by wear. The ignition cylinders, however, are made differently, and have been known to fail. If you’re having trouble with a Saturn ignition lock, there could be an easy solution, but be prepared for the opposite, just in case. Otherwise, don’t sweat; we’ll do what we can to fix the problem, and it might even be easier than you thought.