Let's face it. Vehicles are complicated machines, each having thousands of parts. And since they're subjected to heat, cold, vibrations, bumps and much more, these parts wear out and need to be replaced.
When your service advisor says you need a new part, you may have many options. Let's say you need a new muffler. One choice would be to get exactly the same part that was installed when the vehicle was manufactured. The advantages are that it will perform the same way as the one it's replacing and will likely last about the same amount of time as the original.
Some mufflers are made by the same companies that supplied the automaker when your vehicle was new (they call that an OEM part—Original Equipment Manufacturer). And often those are the same as the part you'd buy from a dealer. A reputable vehicle service facility will know which ones these are because they replace mufflers all the time and do their homework.
The good news is there are many different mufflers available from several manufacturers. These are called aftermarket parts. Some of them may use different metals or a different construction technique. Some may sound a little sportier while some may make your engine perform better. Your service advisor will discuss what your driving habits are and help choose the part that's best for you.
You may be able to get a part that's better than the one originally installed. Here's an example. A repair shop discovered one owner's vehicle had developed cracks and leaks in the hoses that attach to the heater core. They were made of plastic, and heat and pressure had caused the originals to crack. The service advisor recommended they replace it with an aftermarket part that was made of aluminum instead, one that was more durable than the original part.
Some aftermarket parts cost more, some cost about the same or less. Depending on how and where you drive and what you want out of your vehicle, you can decide to buy more economical parts which might be the best fit for your needs. Or you may decide to upgrade to a better, more expensive part.
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