Why is my Ford Transit Custom's engine making a knocking noise?

I recently purchased a Ford Transit Custom and I've noticed that the engine is making a knocking noise. It doesn't seem to affect the performance, but I'm still concerned. What could be causing this and should I address it immediately?

It's normal for a diesel engine to make some noise, but if the knocking is excessive or you notice a decrease in performance, it's best to have it checked by a mechanic. They can diagnose the issue and make any necessary repairs.

The knocking noise could be caused by low oil levels or worn out spark plugs. Check your oil level and replace your spark plugs if needed. If the noise persists, it's best to bring it to a mechanic for further inspection.

I had a similar issue with my Ford Transit Custom and it turned out to be a faulty fuel injector. It's a common issue in these vehicles and it's best to have it replaced as soon as possible.