You’re well aware when you buy a used car that the vehicle’s been around the block a few times. That means the car’s parts will most likely wear out quicker than on a new car. Knowing what parts fail most often and the average cost of fixing them can help you know what to expect regarding common replacements and repairs. Below, we’ve put together a list of the most likely to wear out car parts .
The battery’s job is to provide all of the electrical components in the car with a jolt of electricity so that the car can start. Most batteries become weak and need replacement after 4 to 6 years. In high-heat climates of the southwest U.S., batteries are taxed during hot weather and can wear out even faster, according to the Car Care Council . Symptoms of a weak car battery are the car being slow or difficult to start. The check engine light may also flash on and off.
Average battery replacement cost: $75-$140
The car’s suspension, made up primarily of shocks or struts, keeps the car running smoothly and helps guarantee that you can maintain control of the vehicle while driving. Generally after 50,000-75,000 miles, shocks and struts are likely to become soft. Symptoms of a weak suspension system include dips and nose dives when the car goes over bumps, maneuvers through potholes or stops quickly.
Average suspension replacement or repair cost: $250-$1,600
The water pump circulates coolant from the car’s radiator to the coolant system, then into the engine and returns it to the radiator. If the water pump isn’t working properly, the car’s engine could overheat, causing serious damage. Water pumps  do wear out over time—usually in 6 to 8 years or 60,000 to 90,000 miles. Symptoms of a failing water pump include leaking coolant, car overheating and failure to start.
Average water pump replacement cost: $300-$700
As its name suggest, the fuel pump has the vital job of transporting fuel from the car’s gas tank to its engine. Fuel pumps tend to require replacement around 60,000 miles. They generally offer no symptoms prior to failing.
Average fuel pump replacement cost: $450-$700
The part of a car’s brake system that requires replacement the most frequently are the brake pads, which usually need to be changed every 3 to 5 years or 30,000 to 70,000 miles. How often will depend on the weight of the vehicle—heavier vehicles require more frequent replacement. The type of driving you do also affects brake life. Stop-and-go traffic wears out brakes more quickly than highway driving. Signs that brakes are failing  include a high-pitched squeal, grinding and/or vibration when you brake.
Average brake pad replacement cost for the entire vehicle: $300-$1,000
Considering that tires travel for miles to get a car where you want it to go, it’s not surprising that they wear out fairly quickly. Most tires require replacement every 5 to 7 years. How often you need to change tires will depend on the type of driving you do and where. If you drive aggressively or over rough terrain, you’ll need to replace tires more often. Tires can also wear out more quickly if your car is misaligned. Signs that a car’s tires are wearing out  include uneven or thin tread (less than 2/32 of an inch) and blisters, bulges or cracks on the side of the tire.
Average tire replacement cost for the entire vehicle: $400-$1,800
A car’s transmission  shifts gears so that power can be relayed to the wheels and the car can move. Though a car’s transmission is generally designed to last the life of the auto, some fail at 70,000 miles or above. This may occur if the car is used for towing or high-speed driving. Signs that a transmission is failing include a slipping sensation, rough shifts and a delay to move forward when you shift into drive.
Average automatic transmission cost: $1,800 to $3,500