Why is there a knocking sound when I turn my Vauxhall Zafira Life on?

I have noticed a knocking sound coming from the engine when I start my Vauxhall Zafira Life. It only lasts for a few seconds and then goes away. What could be causing this and is it something I should be concerned about? Thanks.

The knocking sound is most likely caused by a worn out serpentine belt tensioner. This is a common issue in Vauxhall Zafira Life models and should be addressed as soon as possible to avoid further damage to your engine.

Another possible cause of the knocking sound could be low oil pressure. Check your oil levels and if they are low, top them up immediately. If the knocking persists, take your car to a mechanic for further inspection.

It could also be an issue with the engine's timing chain. This is a more serious problem that requires professional attention. Be sure to take your car to a reputable mechanic as soon as possible to prevent any further damage.