When your car needs repairs, there are some fixes that can wait until you can better afford to have them done, but some that should be handled as soon as possible, even if those needed repairs don't seem to interfere with your driving ability. Note a few of those needed repairs here so you can understand why it's so vital to have them addressed quickly, and can immediately schedule an appointment with your mechanic when you notice any of these problems.
You never want your car to be without enough oil, as oil helps to lubricate and cool all its parts. However, just adding oil to the engine on a regular basis is not the solution for an oil leak; that leak can drip onto the exhaust system, electrical wiring, or rubber hoses, causing damage and corrosion to all these parts. Hot oil may literally eat through the rubber of hoses, allowing fluid leaks, or through the protective coating that is over electrical wiring, causing electrical shorts. To avoid this potential damage, and to ensure the leak doesn't get worse over time, have it fixed as soon as you notice it.
If your vehicle sputters when it's idling or when you start it, you may be tempted to ignore this problem if you can still operate the car. However, sputtering often means that the engine is not getting sufficient fuel or oxygen; the fuel pump might be going bad or the oxygen sensor may be failing. Whatever the cause, this sputtering usually puts more wear and tear on the engine as it works harder to maintain proper combustion. If you ignore this problem, it may also simply get worse so that the car begins to stall completely, and eventually you won't even be able to restart it.
If the vehicle's muffler suffers some damage, you'll soon know! The sound is unmistakable and usually only gets worse over time, as corrosion or holes in the muffler just get larger. However, the noise is not the only reason to have the muffler replaced as needed. The exhaust system helps maintain proper combustion in the engine by pulling out excess oxygen and emissions; when the muffler gets corroded, it may not be able to pull those fumes out of the engine, so the engine begins to sputter or run very roughly. You may then see decreased gas mileage as the muffler gets worse. To avoid these problems, have the muffler replaced as needed.