What's That Knocking Noise Coming from My Ford Fiesta?
If you're hearing a knocking noise from your Ford Fiesta, you're not alone. This is one of the most common concerns we see at our Walsall garage, and it's something that definitely needs attention. The good news is that most knocking sounds have identifiable causes, and once we know what's going on, we can help you make the right decision about repairs.
Over the years, my dad and I have diagnosed hundreds of Ford Fiestas with various knocking sounds. What we've learned is that the location, timing, and type of knock can tell us a lot about what's happening under the bonnet. Let me walk you through the three most common causes we see.
Engine Knock from Poor Quality Fuel or Carbon Build-up
Engine knock, sometimes called pinking, is when you hear a metallic tapping sound that gets worse when you accelerate or go uphill. This happens when the fuel in your cylinders ignites at the wrong time, creating pressure waves that knock against the cylinder walls.
In Ford Fiestas, this is often caused by using lower octane fuel than recommended, or carbon deposits building up in the combustion chamber over time. The engine management system tries to compensate, but sometimes it can't prevent the knock completely. When we see this issue, we'll show you exactly what's happening with a video inspection and discuss whether a good engine clean, higher octane fuel, or further investigation is needed.
Worn Engine Bearings Creating Rod Knock
A deeper, more rhythmic knocking that matches your engine speed could indicate worn big end bearings or main bearings. This is more serious than fuel knock because it means internal engine components are wearing against each other with insufficient lubrication.
This type of knock often gets worse as the engine warms up and may disappear briefly when you first start the car cold. Ford Fiesta engines, particularly higher mileage ones, can develop bearing wear if oil changes have been missed or the wrong oil specification has been used. We'll always show you the evidence before recommending any work, because bearing problems usually mean significant engine repairs or replacement.
Suspension and Drivetrain Knocks During Turning or Braking
Not all knocking comes from the engine. If you hear knocking when turning corners, going over bumps, or during braking, you're likely looking at suspension or drivetrain issues rather than engine problems.
Common culprits in Ford Fiestas include worn CV joints, particularly the outer ones which click when turning, or suspension components like drop links and shock absorber mounts. These sounds are usually more noticeable at lower speeds and when maneuvering. The good news is these are typically more straightforward repairs than engine issues, and we can show you exactly which component is worn using our video diagnostic approach so you can see what needs attention.
