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How to Read a V-Belt Size


A v-belt is the main component that turns certain engin […]

A v-belt is the main component that turns certain engine accessory pulleys. An Automotive V Belts operates different engine accessories such as the alternator, power steering pump, water pump and the air conditioner compressor. The belt is driven around each accessory pulley by either the crankshaft pulley or another pulley that the v-belt operates. Some vehicles come equipped with as many as three v-belts. Excessive turning around the accessory pulleys can cause the v-belts to develop cracks and tears. You should change your V-belt before it breaks because it will cause the engine accessories stop working.

A V-belt is a part of your power transmission or a component of your HVAC system. Before you can work with a V-belt you should know where it is, so consult with the owner's manual of the system you're working with. The function of a V-belt is to link together rotating shafts. Because the shafts are rotating, the V-belt must remain flexible. It is useful to change the belt because of the flexibility of V-belt.

Power down the system you're working with. Wait for the system to cool down completely. A great amount of heat can be produced by the rotating shafts of the system.

Remove any part of the system that is blocking you from accessing the V-belt. Consult your owner's manual if necessary. For example, to get to a V-belt of your transmission, you must first take off the drive guard.

You should slip your fingers on the underside of the belt, then stretch upward to release the belt.

Pull the stretched belt away from the system to remove it. You may need to stretch it gently upward or downward to get it off the system.

Stretch out the new V-belt with your hands. Then, put it in place in the system, stretching it upward or downward, just as you did the old V-belt, to secure it in place.

A V-belt can not only transfer power from one engine element to another, but also change the speed and torque of engine components. The latter is done by installing a belt with a different pitch angle. All V-belt numbers start with either a 4L or 3L, which indicate 12.5mm or 9.5mm belt widths. After every prefix is a three-digit number that indicates the V-belt's length in inches.

Read the outside surface of the belt for the prefix 4L or 3L.

Read the three-digit number after the prefix to identify the belt's length. For example, if the belt reads 4L460, you know the belt is 12.5mm wide, with a 46-inch outside circumference.

Subtract 2 inches for 4L belts or 1 1/2 inches for 3L belts to determine the inside circumference of the belt. Using the same example, the 4L460 V-belt has an inside circumference of 44 inches.