Locate the Serpentine Belt on any Car Before buying...it Could Save You Money

A serpentine belt is a thin flexible fiber-reinforced rubber belt that is powered by the car engine. It turns a series of grooved pulleys to power the engine accessories, such as the air conditioning compressor, power steering pump, fan, generator, etc. It is sometimes referred to as a Poly V^Ò belt, which is a Trademark registered to Goodyear.

Effect of engine temperature

Before the invention of the serpentine belt, V-belts tended to dry out and break due to the heat experienced under the hood of the car. When that would happen, one, or several, or all of the engine accessories would stop functioning and could disable the power steering, or the water pump, or the generator, or even the engine fan trying to blow cold air over the hot radiator.

Solution…Cooler running, longer life, greater mileage.

The reason a serpentine belt cools faster boils down to what might be called the surface to volume ratio. The serpentine belt is much thinner than a V-belt, thereby allowing for greater heat dissipation. It is typically about ¾" to 1" wide and only about 1/8" thick

For example, if a V-belt is ½" on a side, and is approximately square, its circumference is 1". Its cross section is ½" x ½", or ¼ sq. inch.. So the surface to volume ratio is 1 divided divided by 1/4^th, or 4.

The serpentine belt, about ¾" wide and only 1/8" thick, has a circumference of ¾" + ¾" + 1/8" + 1/8" =1 ¾". Its volume is only ¾" x 1/8" or 3/32 of a square inch. So its ratio of surface to volume is 1 ¾ divided by 3/32, or roughly 18, or more than 4 times greater than a V-belt. Because the serp belt is so thin, and has lots of surface relative to its volume so it cools more quickly than a v-belt, hence lasts a lot longer.

The serpentine belt has several small V grooves, each about 1/8" wide, spread lengthwise on this inside surface that wraps around the pulleys that drive the engine accessories. .

Wear is inevitable

However, even a serpentine belt will eventually degrade, crack, and break but it will last longer than a conventional V-belt before breaking. For information on how to avoid this undesirable event, consult your user manual, or find hundreds, if not thousands, of articles on this subject on the Internet.

Tip to a car buyer

Replacing a serpentine belt can be a job for a do-it-yourself or a $100 job in a garage depending on the engine design. User-friendly manufacturers design the engine so that the serpentine belt can be simply removed and replaced. But some, who are not user friendly, stick an engine mount in the way, and that requires that the car be placed over a “floor jack" (the ones with the six foot long handle), which is then cranked up to take the weight of the engine.

Note: The typical car engine is usually bolted to the car frame in three places with “engine mounts", each containing a several washers and also a fat rubber washer to give the engine a little spring.) Then the interfering engine mount is disassembled and the new serpentine belt is slipped through the gap and the engine mount parts replaced. There goes $100.

Look under the hood before buying any car

When buying a car, always insist on making sure that the serpentine belt replacement is a penny ante replacement rather than a major undertaking. Most sales people don’t know where the belt is, much less how much it costs to replace it. Ask the service department for this information and leave some money in your pocket by not buying a car where replacing the serpentine belt requires jacking up the engine and temporarily disassembling an engine mount.