Originally posted 2017-07-31 02:21:41.

The modern designs of engines has cut off most of the factors that usually cause engines to develop faults regularly, such includes: automatic fault detecting system, diagnosis suggestions, and digital indicators, etc. All these has made the engine repair and maintenance appear simple to some individuals, but the facts still remains that most mechanical engineers still find it difficult in carrying out repair in these modern engines. Though the attached mechanisms are good and will aid in fault detection but what of the situation where the fault detector is the one having the fault alongside with some parts of the engine? How can the engineer know the source of the fault in such condition? These and many more questions have made it necessary to have a thorough knowledge of modern engines before working on any of them.

Recently, a man complained to me of how his new jeep developed a vibration fault such that anytime his speed exceeds 80km/hr. the motor will start vibrating while on motion, he took the vehicle to a mechanic who listed some items for him to buy because they need to be replaced. At the end of everything he spent more than N200,000 for the repair. Though the sign stopped but he realized after few days that the sensors attached to the bumpers to automatically stop the vehicle from hitting nearby objects during turning had stopped working after the mechanic worked on the car, taking the car back to the mechanic he recommended buying new sensors which after their installations the problem persisted till date, a very sad story I would say.

Modern engines uses pulley drive system which is mostly used with belts in their functions, and these belts do get weak over a period of time depending on the usage and quality. Though this is a minor issue in engine maintenance but its negligence had caused a lot of wrong diagnosis in engine fault detection and repair.

When a weak belt develops its signals it may be wrongly detected by any digital devices to mean another thing which may lead to buying and changing of parts that are not actually the real cause of the problem, one way to avoid such incident is to check for the specified period of time any belt in your engine is supposed to stay before changing it.

Some common faults weak belt could cause are;


The weak belt can cause a serious ignition problem because the pulley from the ignition motor needs to transmit a rotating motion to the engine flywheel or shaft at a high and instantaneous speed within a short time. So if the belt had gone weak it will make the motor transmission speed to be reduced such that if the engine ignition system is not in good condition the engine may find it difficult to start.


Most engines uses pumps to circulate the water from the radiator to the internal parts of the engine, the action is usually a continuous one provided the engine is in its operational state. When the belt that drives the pump which is usually connected to the major engine shaft had gone weak or loosed, the pumping speed will reduce thereby affecting the rate of water circulation and causing the engine temperature to be higher than normal.


Another sign of weak or loosed belts could be a slight reduction of the engine power output which is as a result of its reduced speed. As you can see in the above diagram, if the engine has many belts connected to it and some or all of them has gone weak it will cause its dragging force to increase thereby reducing the overall engine speed which is clearly indicated by its work output or speedometer.


Another problem weak and loosed belt could cause is to slip off or tear apart from the pulley if extra force is applied trying to force its speed, this usually occur when an engine is operating at a very high speed with weak belts. And incidents like that will lead to other serious faults to the main engine and other components.

if you find this post useful and have any personal contribution to it which will be useful to other members and visitors of the website please use the comment form below this post to do so.

  • Yum