Auto parts dealers maintain an extensive inventory of replacement auto parts and sell them either to individuals or directly to automotive repair shops. In addition to actual replacement auto parts, many auto parts dealers also sell motor oil, antifreeze, transmission fluid and other common automotive maintenance items. Some auto parts dealers also perform free services, such as battery testing and diagnostics, while also providing advice and information about automotive problems.
In some cases, auto parts dealers are subsidiaries or departments of auto parts manufacturers. This is true of ACDelco and NAPA, as these companies manufacture common auto parts, such as spark plugs, air and oil filters, belts and brake pads in addition to selling these parts through their retail outlets. ACDelco is somewhat unique in that the company is the original equipment manufacturer for General Motors, whereas most automotive companies manufacture their own original parts; however, both ACDelco and NAPA also offer other auto parts either from other original equipment manufacturers or aftermarket companies.
Unlike ACDelco and NAPA, most auto parts dealers sell auto parts manufactured by other companies. This type of auto parts dealer includes industry-leading companies such as AutoZone and Advance Auto Parts.
An increasing number of auto parts dealers operate exclusively on the Internet, with no brick-and-mortar retail presence. While these auto parts dealers lack the individual attention and customer service of traditional auto parts stores, they can offer lower prices due to reduced overhead costs.