Mechanic Underneath Car on Lift (© Andersen Ross/Digital Vision/Getty Images)

Like real estate and relationships, cars require upkeep. If you neglect to change the oil, ignore the check-engine light or skip routine servicing, you're setting yourself up for a rude — and expensive — awakening. According to Art Jacobsen, vice president of, which publishes an online database of the most common and expensive check-engine-related automotive repairs, the key is to diagnose your car's problems early: "You've got to tackle it; address it when it's small, before it escalates." Here are the 10 most expensive vehicle repairs and what you can do to avoid them.

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10. Replace Turbocharger/Supercharger Assemblies

Turbochargers and superchargers help force air through the engine, allowing it to use more fuel, generate a bigger explosion in the cylinder and increase power. These devices typically operate at high rotational speeds, which make them vulnerable to damage and susceptible to heat. When they go bad, it can cost about $1,600 to replace them, with related repairs spiking the price by $700 to $3,000. If you're lucky enough to have a turbocharger or supercharger, you'll need to take care of it. "Make sure you have the right amount of oil in these units," Jacobsen says, noting that too much can be just as bad as, if not worse than, not enough.

9. Replace Torque Converter Assembly

The torque converter assembly is a hydraulic coupling between the engine and the transmission. It's similar to a clutch in that it allows you to come to a stop in an automatic-transmission vehicle without stalling the engine. But when the torque converter overheats, it can spring leaks and its parts can warp, and a busted torque converter may prevent you from starting — or more disastrously, stopping — your car. One way to avoid overheating this part, and incurring roughly $1,800 in repairs, is to not rev the engine while you have your foot on the brake.

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8. Replace Catalytic Converter

Catalytic converters, which detoxify exhaust emissions, are important when you're getting a smog check and if you care about your car's impact on the environment. Most are built to last for 15 to 20 years, and before they go kaput, there are plenty of warning signs. Two culprits are busted oxygen sensors and misfires, which happen when fuel catches fire as it passes through the engine. When a catalytic converter fails, it's pricey: Repairs can cost up to $2,692. It's the parts that are expensive, not the labor. "They contain platinum, palladium and rhodium — three of the most precious metals known to man," Jacobsen says.

7. Replace Hybrid Battery

A hybrid battery is often bundled with an integrated motor-assist battery, which charges it. Change one and you have to change both — to the tune of about $2,700. Because the technology is fairly new, it can be difficult to troubleshoot hybrid engines. "Hybrids are great, but when something goes wrong, you better have your checkbook ready," Jacobsen says. That's because there are a limited number of mechanics servicing hybrids and because parts are scarce. Hot weather in the South and Southwest taxes these batteries. To avoid repairs, you're best off driving them in mild climates.

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6. Replace Injection Pump

A clogged injection pump, the device that delivers fuel into the engine's cylinders, is a relatively common problem for drivers, and the repair costs can vary widely. A Honda fuel pump might run a couple of hundred dollars and be straightforward to change. But in trucks and SUVs, the repair can cost upward of $2,900 because it's labor-intensive, requiring the mechanic to put the vehicle on a hoist and disassemble its rear. If you follow your vehicle's scheduled maintenance program and change the fuel filters regularly, your fuel pump should stay clog-free.