Service Maintenance and Repair ROI_October 2021

AROUND THE ENGINE

Follow the 4T guidelines during belt system servicing 4T was created to introduce a simple best practice process during the service or installation of belt system kits and components, helping to prevent the chance of fitting errors that can lead to premature belt failure. The four ‘T’s are: ■ Temperature Do not attempt to start work until the engine has completely cooled down - this can take up to 4 hours ■ Tools The correct tools must be used in accordance with vehicle manufacturer (VM) instructions - locking tools are recommended for a reason, Tippex doesn’t lock! ■ Torque Use a torque wrench to tighten all bolts to the correct VM specifications - that includes degrees of rotation where stated, as each step is critical for obtaining the correct clamp load for the fixing ■ Tension Belt tension must be accurate, correct and to VM recommendations - following the recommended number of engine revolutions as part of the setup is critical to a setting the tension correctly.

Belt and tensioner diagnosis A broken timing belt and/or tensioner can cause engine failure, which can be catastrophic, time consuming and very expensive. That’s why it’s imperative that technicians always check the system for wear during a routine service, and always replace it at the vehicle manufacturer’s recommended change point. Diagnosing what causes a timing belt to break is not straight forward, but common reasons for failure can usually be classified:

Straight break Caused by belt ‘crimping’, usually because of fitting or handling error

Jagged break Caused by incorrect/excessive tension (fitting error) or a foreign body entering the drive system

Sheared teeth Caused by incorrect tension and misalignment (fitting error), or because the recommended change point has been exceeded

INA belt system specialist, Tim Adams, said: “We are not trying to teach mechanics how to suck eggs, but it is amazing how many problems can be created by not following these simple rules in the workshop. “Being familiar with a particular engine timing setup doesn’t mean you no longer need to look at the instructions, as that’s when problems can occur. It is not uncommon for VM setup instructions to change, or for different designs of OE tensioner to be introduced during the engine’s lifetime. Each new tensioner design can have its own unique setup instructions, which must be followed to the letter to guarantee an accurate and professional results. “4T is easy to remember, and adhering to its principles will help to prevent fitting errors, saving time, effort and money for both the garage and its customers.” Investigate and repair If a driver notices any unexplained noises or vibrations coming from the engine, the cause should be investigated by a technician immediately. If a timing belt replacement is required, our partners, along with the vehicle manufacturers, recommend that all the belt system components need to be changed at the same time to reduce the risk of major engine damage caused by premature failure. By using the wide range of Timing Belt KITs, technicians will save time by having everything they need to carry out a professional repair in just one box, with the Timing Belt Kits with Water Pump range also including the belt driven water pump and even the thermostat where required.

Cracked back Caused by heat exposure and/or the change point exceeded

Side wear/polishing Caused by misalignment (fitting error)

Worn teeth flanks Caused by incorrect/excessive tension and misalignment (fitting error), and/or exceeding the change point

Marked belt back Caused by incorrect tension and alignment (fitting error) or a foreign body entering the drive system

Gap (land) wear Caused by incorrect/excessive tension (fitting error)

Contaminated belt (grease/oil) Caused by other defective or damaged components or an incorrectly installed timing belt cover.

Signs of a broken tensioner include the following: ■ Worn end stop/broken stop pin ■ Caused by an incorrect tension (fitting error) ■ Contact damage on pulley rims ■ Caused by misalignment (fitting error) or defective components, such as a worn water pump bearing. Note:

The condition of the timing belt system cover is very important, as there must be no cracks, holes, or any other damage to the covers through which the timing system can be contaminated. Check for oil leaks, as the environment under the timing cover must be clean and dry, as automatic belt tensioners are not designed to be lubricated and can prematurely fail if they become contaminated by oil.