The world of auto parts is a murky one. There are so many manufacturers and quite a range of costs that one can easily be misled, and it is a situation that is only getting worse.

Back in 2008 attendance by traditional vendors at the SEMA show, the big aftermarket parts trade show, was down over 30 percent, a result of the economic downturn. This made me especially surprised by the number of newcomers, specifically Asian manufacturers. In particular, I was struck by the range of parts they offered: water pumps, alternators, starters, oil filters, brakes, batteries, ignition components, sparkplugs, and everything else that gets replaced during regular maintenance and repair. And these were parts for the full range of imports and domestic models, parts for all the popular models.

The resounding theme of these suppliers was “Lower Prices!” Like a carnival atmosphere, these guys were barking pitch after pitch, each booth claiming their wares were the cheapest ones in town.

A Bad Flashback

For an instant, I was brought back to an earlier time in my life, to 1974 when I was the head technician at a repair facility in New Jersey. A new “mobile” parts supplier (a guy selling parts out of his van) had come by touting his new line of low-priced ignition parts. A new set of GM points caught my eye, and they were $4 cheaper than the OEM part and, as I was told, “worked just as well.” I was skeptical, because the design was different, but the shop did a high volume of tune-up work, so my boss saw this as an opportunity to increase his profits. So despite my warning, he bought 30 of them, which we went through in short order.

We restocked a week later and my boss was all smiles at the money he had saved. But about three weeks later we started getting calls from upset customers, all with the same complaint: Their cars would stall and not restart. We tracked the problem to the bargain ignition point sets and we ended up having to tow the cars back to the shop and replace the points again. Not only did my boss have to pay for the tow jobs (a few were over 100 miles away), but he also had to buy new point sets and pay the labor to install them. In short, the whole debacle cost him a few thousand dollars. He banned the guy in the van from our premises and determined from that point forward to offer only the highest quality parts in all auto repairs. A costly lesson, indeed.

You Get What You Pay For

Not all parts are created equal, and that’s why “the same parts” vary so much in price. But after shopping parts you can get a feel for what the average price should be for a particular part. Be wary of drastic differences: Higher isn’t always better but cheaper almost always means inferior quality.

Let’s take a look at some of the common replacement parts and what the effects of “fixing it on the cheap” can be.

1. Brakes - Brakes are one of the most common repairs people have done on their cars, and one of the common areas in which corners can be cut. Brake shoes and pads are friction materials that rub against brake drums or rotors, slowing the rotation of the wheels. The friction material is usually made of a semi-metallic mixture (ground up metal mixed with other stuff). The friction materials of cheaper pads or shoes tend to contain more metal and thus are of a harder composition. Pads and shoes are bonded to a steel backing and in cheaper pads the bonding material is often inferior, unlike the more expensive pads that are riveted or bonded with a high quality bonding.

Poorly bonded brake pads and shoes wear out faster and can possibly fail to stop your vehicle for several reasons. The harder composition of the cheaper pads and shoes generates more heat when the brakes are applied and doesn’t dissipate the heat as well. This heat crystallizes the glue, which causes the pad or shoe to separate from its backing. The use of inferior glue speeds up this process in a vicious circle. In addition, the hard composition of the cheaper friction material tends to crack when heat is applied. To top it all off, the contact of the harder friction material on the drums or rotors wears out these parts more quickly.

In choosing drums and rotors, you should always buy the best products available. Cheap drums and rotors are made of sub-standard steel and therefore wear out prematurely, especially when they come in contact with sub-standard friction materials, as mentioned above. Rotor and drum warpage and premature wear are common when cheap parts are used in a brake job and warped rotors result in decreased braking performance, which is a safety hazard.

2. Batteries - In a cheaper battery, the case is less sturdy, the quality of the posts is compromised, there are fewer internal plates and poor plate connection can cause the battery to fail when it is subjected to vibration. Just because it “looks the same” as your old battery doesn’t mean that it matches the performance of your OEM unit. Furthermore, installing a battery that is rated at fewer cold-cranking amps than what is required by the manufacturer is just asking for trouble.

3. Oil Filters - The oil filter keeps dirt out of your engine, which is an important job if you want it to last. Quality oil filters have a check valve, designed so that the engine has oil pressure immediately upon cold startup, preventing wear. Many cheap filters lack this critical element, or even worse, don’t have the fine filtering media necessary to capture the smallest particles of dirt. This is not an area to try to save a few dollars.

4. Alternators/Starters/Water Pumps - Alternators, starters, and water pumps are the sorts of parts that, when they fail, can be rebuilt. When this is done right, the end result is pretty much a brand new part, although it is sold for less. Cheap rebuilt parts, however frequently lack attention to the details that result in dependable performance. The companies that produce low quality rebuilds replace only what is obviously bad and leave the rest, hoping the part will outlast its short warranty. Selling these sorts of parts as “rebuilt” is really a misnomer, as it would be more accurate to describe them as “repaired.”

5. Spark Plugs and Ignition Components - Spark plugs and ignition system components power the engine, and low quality products usually result in poor performance or a car that doesn’t run. Years ago I did an investigative report for a local TV station. It involved taking two GM ignition modules, one an OEM part, the other, a knockoff. Both units looked the same and had the same electrical connections and mounting configuration. Even the cases looked the same. But once I opened them up, the similarities came to a screeching halt. The OEM part was stuffed full of electronics, whereas the knockoff had a mostly empty case. You only had to look inside these units to understand the significant price difference.

As for sparkplugs, always go with an OEM-specified plug, especially true in today’s age of computer-controlled engines. Automotive computers are designed with a certain set of parameters from the factory to achieve maximum efficiency, power, and tailpipe emissions. Put a cheap sparkplug in the engine and you throw the computer into a fit trying to compensate for the lack of spark.

While some cheapskates may balk at manufacturer recommendations like using expensive platinum sparkplugs, platinum plugs burn hotter and longer, hence they deliver maximum fuel efficiency and power. In addition, the platinum holds up longer to the high electrical voltages used in today’s ignition systems. Installing a cheap plug in a vehicle that requires a platinum plug results in poor fuel efficiency, poor performance, high tailpipe emissions, and other issues.