1991 Mitsubishi Eclipse Balance Shaft Drive Belt Replacement Cost

The term “Drive Belt” is a generic term used to describe a set of belts that are used to drive engine accessories. The most common drive belts are the alternator belt, power steering pump belt, and air conditioning compressor belt. Some engines use balance shafts to balance internal rotational forces from the engine. While most are driven by timing chains or the timing belt, some have dedicated drive belts known as 'balance shaft drive belts'.

While the engine is running, the crankshaft pulley is constantly spinning. This provides an opportunity to drive other mechanisms by means of a belt. Much like the timing belt or timing chain, the balance shaft belt will wrap around the balance shaft and crankshaft, and secure to toothed gears on both shafts. This causes the balance shaft to rotate at the same speed as the crankshaft, and always remain synchronized.

If the balance shaft belt breaks, there may be strange rubbing or grinding noises from the front of the engine. This is because the timing belt is likely chewing through the balance shaft drive belt as it is likely resting on the teeth of the timing belt. If it is not changed immediately, the engine will being running roughly, and vibration will be evident throughout the vehicle. As a worst-case scenario, internal engine damage may occur due to the balance shaft belt dislodging the timing belt or other timing components. The check engine light will illuminate on the dashboard in the event of total failure or breakage of the balance shaft belt and the vehicle may not start or stay running.

It is not recommended to drive a vehicle suspected of timing component damage, and the balance shaft belt and tensioner are responsible for the timing of the balance shaft to the engine. If the vehicle will run, operating the vehicle may result in damage or total failure to the engine.