A used car inspection can save you a lot of grief and money down the road. Vehicle history reports are helpful, but investing some time and money in a trusted mechanic to check over a potential purchase can pay off big time. If you don’t have access to a mechanic, however, there are some things you can look for on your own before buying that will help you determine if the car or truck in question is worth your hard-earned dollars. So grab a flashlight and put on your detective hat to see what your potential used car purchase may be telling you.
1. Rust Is an Enemy
Perhaps more than any other issue during a used car inspection, rust is a surefire signal that it’s time to walk away. On an older car, some surface rust might be considered normal, but on a recent model, rust may be indicative that the vehicle was driven in harsh winter weather and not properly cared for in terms of corrosion protection. Road salt and brine have a nasty habit of making their way into deep recesses where they attack and metal that isn’t protected. It may also show that the vehicle was involved in an accident and repairs were not made properly. Shiny new paint may hide shoddy repairs underneath. Look for body filler using a refrigerator magnet covered in masking tape (to protect the car paint). Place the magnet anywhere a metal body panel looks wrinkled, irregular, or just odd. The magnet should stick to the body panel if it is steel. If the panel is steel but the magnet won’t stick there may be hidden body repair and body filler.
Don’t just look at the shiny painted parts, take your flashlight and a pair of safety goggles so you can get a good look underneath the vehicle. Use your finger to tap on any areas that look crusty. Anything that looks like rusty metal flakes is bad. Check things like fuel lines, brake lines, parking brake cables, and anything else that looks crusty. Suspension pieces like control arms can also rust so don’t skip them. Use your smart phone camera to take pictures in places you can’t reach or see easily.
Rust is expensive to fix, and it is a progressive concern — over time, it will definitely get worse — so it’s better to find the cleanest, corrosion-free car you can afford rather than accept rust while searching for a bargain.
You can tell a lot about how a car was treated simply by how it looks — and in this case, it’s fine to judge a book by its cover. An owner who didn’t care enough to avoid getting the car scratched or dented, or who never replaced missing trim pieces, side mirrors or interior parts, also likely avoided regular oil changes and other crucial maintenance. The same can be said about the interior. If the inside looks trashed then the drivetrain may not be much better.
We’re not saying a good-looking car guarantees a trouble-free purchase, but we’re confident that an automobile that looks like it has been through a lot will likely hit your wallet hard down the road when it comes to repair costs and other hassles.
3. Smoke or Unusual Noises
Our quick and dirty used car inspection process instantly eliminates any vehicle that smokes from the tail pipe. White smoke may indicate a bad head gasket, which could leak coolant into the combustion chamber, while dark smoke can indicate the car is running rich (which could result from a bad oxygen sensor, spark plugs or wires) or that it’s burning oil. Ask the seller to not crank the vehicle until you get there so you can observe a “cold start” situation. A “cold start” will reveal other exhaust smoke causing leaks that may disappear once an engine is warmed up. Very loud clicking or knocking is another indicator that something is amiss with the car. Anything that sounds like metal hitting metal is a bad sign. Noises that change speed with engine RPM should also raise red flags. If it’s leaking any fluids — to the point where you can see it in action on the pavement below — it’s time to walk away.
4. Diagnostic Scan
Just because the check engine light is not on doesn’t always mean things are okay. Every car, truck and SUV built since 1996 has been required to use the OBD II system standard to help ensure emissions compliance. This is good because it means you can use a common hand-held code reader to check the system for any issues. All OBD II plugs are required to be the same no matter the vehicle manufacturer, so there’s nothing special to use. With a code scanner you can check for any pending fault codes that could soon trigger the check engine light. You can also check to see if the onboard diagnostic systems are functioning and ready. Things like if the catalytic converter is functioning, whether the oxygen sensors are within spec, or even if there is an ignition misfire can all be discovered. A car might drive fine but still hide potential problems. If the on-board diagnostic systems do not register as “ready” then they have not completed their self-test process and there could still be a problem. A vehicle that has multiple system register as “not ready” likely had the OBD II recently reset. If the OBD II system is not fully ready and clear of any trouble codes, it is time to move on to the next vehicle.
Inspecting a used car thoroughly can save you money down the road. Follow our guide and you’ll be in a better position when you’re ready to make your purchase.
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Photo courtesy of MorgueFile.
Having been bitten by the car bug at a young age, I spent my formative years surrounded by Studebakers at car shows across Quebec and the northeastern United States. Over ten years of racing, restoring, and obsessing over automobiles lead me to balance science writing and automotive journalism full time. I currently contribute as an editor to several online and print automotive publications, and I also write and consult for the pharmaceutical and medical device industry.