You drive an old car. Old cars, which are at least 10 years old, have typically seen substantial wear and tear. This is especially true if most of the car's miles have been logged during short trips or a lot of stop-and-go traffic. While today's engines can easily last for multiple decades if they are cared for, they also may have buildup inside various engine components. Some additives can help remove these deposits that can compromise performance.
Your car has high mileage. Regardless of your car's age, if it has high mileage -- at least 100,000 miles -- it also may have various issues in some of the engine components that could affect its performance. Sometimes, additives can improve performance.
Your car has a known problem. Perhaps your car hasn't passed its emissions check, or your fuel economy has dropped dramatically. Maybe your transmission is less-than-perfect, or the radiator isn't keeping the engine as cool as it should be. When your car has a known problem, sometimes certain additives, cleaners or flushes can resolve it and save you from replacing an expensive part.
But heading to your nearest auto parts store or even the auto department of a big-box retailer to peruse the dozens of products should not be your first step in deciding whether to use an additive.
Instead, start by talking to your mechanic about any concerns regarding your car's performance, and see if he thinks there are any additives that might help your situation. If he does, it is likely he has access and experience with products that are sold only to service shops that have undergone substantial independent testing to prove their worthiness.
Ask for detailed information on the products he recommends, and then do your homework online. A simple Internet search should turn up any consumer complaints or investigations. The Environmental Protection Agency, or EPA, and the Federal Trade Commission, or FTC, assess these products for their ingredients and their claims. In addition, many companies producing these products offer details on any testing they have done to give consumers a feel for a product's reliability.
Once you have a good understanding of the products being suggested and can confirm no one is complaining about their results, you can make a determination on whether to use the additive. For many situations, it may be a cheaper alternative to try to resolve the problem with an additive before an expensive part must be replaced or before you feel forced into replacing your car entirely.
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