Q: What Are the Different Drive Belts in Your Car?

Well depending on the year, make, and model, there are different kinds of belts. On today’s newer vehicles a single belt called a serpentine belt is used. It’s called “serpentine” because it snakes around all the drive pulleys, and uses a tensioner pulley and idler pulley to keep proper tightness and to prevent slippage. This one belt design runs to the alternator, which spins the pulley creating electrical power to keep battery at full charge. It then goes to A/C compressor, which pushes refrigerant to keep the inside cool. Then on to the power steering pump, which pumps fluid to your steering making it easier for you to turn the wheel. Some cars have an external water pump as well, the serpentine belt will also run that which flows the engine coolant through your engine and radiator.

The serpentine belt has grooves on one side which rides in mesh with the pulleys and is flat on the other side to glide over the tensioner and idler pulleys. A disadvantage is, if the belt fails, you will lose all accessories that run off of it. An advantage of the serpentine is its ease of removal and installation.

The next type of belt is called a V belt and there are 2 belts used. The belts run off the crankshaft pulley. 1 belt will go to the alternator keeping your battery charged. The other will go to the power steering pump, water pump, and AC compressor. On some newer cars the water pump is internal which we will explain in the final belt. The V belt gets its name from being shaped like a V, the small end rides in the groove of the pulleys. The main advantage of the V belt is, if one fails, you will not lose all functions of accessories. A disadvantage is the manual tensioning.

And last but not least is the timing belt. The timing belt is main artery of the engine. Its job is to keep the crankshaft and the camshaft(s) in time by opening the intake and exhaust valves at precise moments. On interference engines the water pump is also run off the timing belt. It is very important to follow the owners manual recommended replacement of the timing belt. If timing belt fails it may cause catastrophic failure of the engine. It is also recommended to replace the water pump when replacing the timing belt and vice versa.

Timing belts are usually notched on one side and flat on the other, kind of like the serpentine belt. It also runs off a tensioner and idler pulley. Some cars use a timing chain as opposed to a belt. For a timing chain, you could imagine it as 4 bicycle chains connected side-by-side. Timing chains work just like a bicycle chain and runs off of gears not pulleys. Timing belts and chains perform the same function.

In summary, the timing belt, serpentine belt, and V belts are vital to a car’s engine. Always have the belts checked whenever servicing your vehicle and follow recommended replacement intervals from your owners manual or our maintenance scheduler in order to maintain and optimize performance for your car.