Why is my Vauxhall Astra's engine making a loud knocking noise?

I've noticed that my Vauxhall Astra's engine has started making a loud knocking noise recently. It seems to be getting worse and I'm worried it might be causing damage to the engine. What could be causing this and how can I fix it?

It could be caused by a number of things such as worn out bearings, loose timing belt, or low oil level. It's important to have the engine checked by a mechanic as soon as possible to prevent further damage.

You may have a faulty fuel injector or spark plug, which can cause the engine to make knocking noises. I recommend having those components inspected and replaced if necessary.

One potential cause could be using low quality fuel. Try using a higher octane fuel and see if the knocking noise improves. It could also be a sign of a clogged fuel filter, so have that checked as well.

I had a similar issue with my Vauxhall Astra and it turned out to be a faulty crankshaft position sensor. It's a relatively easy fix, so have that checked by a mechanic.