Home / News / Industry News / Checking the V Ribbed Belt Tension is Nessery

Checking the V Ribbed Belt Tension is Nessery


V Ribbed Belt is traditionally found in older motors. A […]

V Ribbed Belt is traditionally found in older motors. A series of v-belts come off the crankshaft, each powering its own individual accessory group such as alternator, a/c compressor etc. Failure to replace a v-belt can cause your engine accessories to stop working as well as engine overheating.

Checking the belt tension. The belt should be at least tight enough so that turning the generator/alternator pulley with a wrench also turns the engine.Use a ruler to find the mid-point on the belt's longest run between pulleys. Use a ruler to find the midway point on the belt's longest run between pulleys. Hold the belt between finger and thumb at this point and move it from side to side. If it is too loose, turning the pulley will just turn the generator/alternator shaft while the belt slips on the pulley. In this particular engine, proper fan belt tension is vital, since any belt slipping reduces the amount of cooling air that is supplied by the fan to the engine. Of course, having the belt too tight can cause premature wear on the alternator/generator bearings.

The alternator/generator drivebelt, also referred to as a V-belt or simply fan belt, is located at the rear of the engine. Because this belt drives both the alternator and the engine cooling fan, the good condition and proper adjustment of the belt are critical to the operation of the engine. Because of their composition and the high stresses to which they are subjected, drivebelts stretch and deteriorate as they get older. They must therefore be periodically inspected.

With the engine off, open the rear hood and locate the drivebelt at the rear of the engine. Check the belt for separation of the adhesive rubber on both sides of the core, core separation from the belt side, and/or severed core.

Also check for fraying and glazing, which gives the belt a shiny appearance. Both sides of the belt should be inspected, which means you will have to twist the belt to check the underside Use your fingers to feel the belt where you can't see it. If any of the above conditions are evident, replace the belt.

To check the belt tension, with your thumb push in on the belt midway between the pulleys and measure the deflection with a ruler. The drivebelt deflection should be about 5/8-inch. If the tension is more or less than this, it must be adjusted to bring the tension into specification.