Should I Worry About High Mileage When Buying a Car?

Mileage is an odd sort of quantity where cars are concerned. On the one hand, high mileage always indicates that the car isn't in as new condition as one would prefer. On the other, the original owner's commitment to maintenance, driving style and the car's operating conditions have more to do with the car's actual condition than the number of miles on the odometer. No matter how you slice it, knowledge is always power when purchasing a car.

Basic Wear Items

Some things always receive a certain amount of wear regardless of the vehicle's operating conditions. Wear surfaces inside the engine and transmission, including seals and bearings, cylinder walls, camshafts, sensors and actuators will always wear to a certain degree, regardless of the maintenance schedule. Chassis components such as shock absorbers, springs, bushings (the rubber isolators in your suspension), motor mounts, wheel bearings and CV joints are also subject to constant, wear-inducing vibrations and movement.

What Kind of Miles Are They?

Above and beyond all other factors, the vehicle's operating circumstances have more to do with its condition than anything else. Periodic stresses due to off-roading, racing and rough roads may not have any immediate impact on a vehicle, but apply those stresses over tens of thousands of miles and everything wears out sooner. Miles accrued in stop-and-go city driving will put far more wear on the vehicle than sustained highway miles. Before buying the car, you need to ascertain whether it accrued 100,000 miles on the highway at 60 mph or on the drag-strip, 1/4-mile at a time.

Regular Maintenance

Aside from the vehicle's operating conditions, vehicle maintenance is the most crucial factor in terms of condition relative to mileage. Some of the best deals out there are government-owned fleet vehicles. County, state and federal agencies are generally religious about following the factory recommendations for oil changes, fluid flushes and other preventative maintenance tasks. If possible, purchase a vehicle that has always used synthetic fluids changed at regular intervals.

Replaceable vs. Non-Replaceable Parts

Don't assume that just because your potential auto has a new engine and transmission with 10,000 miles on them, the vehicle as a whole is as good as one with 10,000 miles on it. Most modern vehicles use a monocoque or frame-less construction, meaning that the chassis welds are what holds the body together. All chassis types bend and twist a little during driving, which slowly weakens the welds and the frame metal, like bending a paperclip back and forth. Over time, these weakening welds cause the chassis to become more and more flexible. The flexing chassis will eventually result in a plethora of squeaks and rattles, and may be severe enough to impact handling, door and panel alignment and window operation.