You can damage your engine if you're not careful to use the right oil filter and replace the oil-drain plug without stripping its threads, or forget a leak-stopping gasket.

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Imagine one of these on every exhaust pipe, with a filter that you get changed every time you change your oil.

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While your oil is changed, the sales associates will offer to change your air filter, perform a transmission fluid change and do a variety of other more profitable services in the hopes of increasing the profit margin.

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