Today’s vehicles rely on serpentine belts to drive alternators, water pumps, and other crucial engine components. You’ll find serpentine belts made from neoprene or, more commonly, EPDM. Both materials offer their own set of pros and cons that affect overall performance and longevity.
All About Neoprene
Once upon a time, most serpentine belts were made from neoprene rubber, a replacement for natural rubber that’s also commonly used in hoses, gaskets, seals, and a vast array of other non-automotive applications. Neoprene’s chemical stability and durability made it an ideal choice for serpentine belt manufacturers in prior decades. With the advent of EPDM, however, neoprene has fallen out of favor with most belt makers.
Neoprene Pros and Cons
Neoprene is a durable material that stands up to a wide range of temperatures without losing its flexibility. A typical serpentine belt made from neoprene can last for 50,000 to 60,000 miles before belt failure becomes a concern. In some cases, neoprene serpentine belts may also be slightly less expensive than their EPDM counterparts.
But after 60,000 miles, neoprene serpentine belts tend to degrade quickly. Not only do cracks eventually form on the belt ribs, but large chunks of rib can also come apart. Even a small loss of belt material can make the belt slip and lose tension, resulting in potential power losses. Neoprene serpentine belts are also more likely to break completely, usually due to advanced wear or serious damage.
A Close Look at EPDM
As more automotive manufacturers demanded longer lifespans from serpentine belts, OEMs turned to ethylene propylene diene monomer, or EPDM for short. Made from synthetic materials, EPDM serpentine belts began seeing widespread use in the early 2000s. Today, EPDM remains the standard material for modern OE and aftermarket serpentine belts.
EPDM Benefits and Drawbacks
A big advantage of EPDM serpentine belts is that they offer a longer lifespan than comparable neoprene. While most EPDM belts are designed to last up to 100,000 miles, it’s not uncommon for these belts to last for nearly double the mileage. EPDM belts also retain their flexibility longer, which means the belt itself won’t lose its tension or form cracks like neoprene belts.
The lack of cracks and other traditional signs of belt wear makes it a bit tougher to immediately spot wear issues, however. Instead, EPDM belts wear out similarly to how a tire loses its tread over time. And just as one would check the tread depth on a tire, the best way to check for wear on an EPDM serpentine belt involves checking the rib valleys with a belt wear gauge. On a worn belt, the gauge will sink into the rib valleys, whereas the tool will simply rest on top with a noticeable gap.
While neoprene belt designs are perfectly serviceable, you’ll appreciate the longer life and improved durability of modern EPDM serpentine belts. But no matter which type of serpentine belt you choose, the most important thing is to keep a close eye on belt wear and change them at the intervals recommended in your vehicle owner’s manual.