Car repairs are always unpleasant. Even minor parts that need to be replaced are an inconvenience because they siphon away your limited time. When your fuel filter, catalytic converter, or alternator fail, the experience becomes far less pleasant. Not only do those components cost more, but the labor involved in replacing them can add hundreds of dollars to the final bill. This is why mechanics will often ask whether you would like the failing components replaced with rebuilt, remanufactured, or used auto parts.

There are pros and cons to each option. Below, I’ll explain what each option offers and their respective drawbacks. I’ll then explain why OEM (Original Equipment Manufacturer) certified parts are usually the best choice.

What Does “Rebuilt” Mean?

Parts that are rebuilt are a combination of original pieces and what has been used to replace failing pieces. For example, suppose your alternator shows signs of failing. It is actually made up of multiple individual pieces, including several terminals, a voltage regulator, and a diode rectifier. A failure might be due to a single piece. If that’s the case, you can have the mechanic simply replace the individual piece that failed to get your car back on the road.

Sometimes, mechanics will use a core. This happens when the failing component from your vehicle is worn to the point that it cannot be rebuilt. The core is taken from another car and the bad pieces are replaced.

One of the drawbacks to rebuilt car parts is that the replacement pieces will be new while the rest of the component will have experienced some wear and tear. The disparity can potentially introduce heat stress and other problems. Moreover, the original alternator (in our example) may still fail in the near future.

Buying Used And Taking Your Chances

A lot of consumers choose used auto parts because they’re less expensive than rebuilts and remans (which we’ll explore in the following section). These components usually come from salvage yards. The advantage is price. Depending on the piece you’re buying, you can expect to save up to 50% from the retail price of a new equivalent.

The downside is that you can never be certain regarding the quality or durability of the piece you’re buying. Depending on the upkeep of the yard, moisture and rust may have caused hidden damage. If you’re only buying a knob for your car stereo or gearshift, there’s very little risk. On the other hand, buying a used alternator is a bad idea - even if it comes with a limited warranty.

Used car parts have their place, especially if you’re purchasing simple pieces. For complex components, stick to rebuilts and OEM-certified remans.

Remanufactured Components: Worth The Investment?

Remanufactured parts (or, remans) are components that have been rebuilt to OEM standards. They’re completely disassembled so every piece can be cleaned and inspected for wear and tear. Any individual pieces that show wear are replaced. Often, remans are entirely new with the exception of the component’s shell (i.e. core).

The advantage to using remans is that they’re built with a much higher level of quality than rebuilts. The reason is because they have to meet OEM standards prior to installation. Plus, due to the higher quality, they usually come with longer warranties. The drawback is that they cost more.

So, which option is best? Your decision will ultimately rest on the type of component you’re replacing and your budget. As noted earlier, simple pieces can be purchased at salvage yards if you’re willing to invest the time. More complex pieces that have failed (i.e. alternator, fuel pump, catalytic converter, etc.) should be replaced with OEM-certified remans.

OEM replacements trump the other options because they’re built by the same manufacturer as that which built the original part. If you’re willing to spend the extra money, that will give you an extra level of comfort and peace of mind.