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More noises your engine makes (and what they mean)

Cars are a vocal lot. Most of the time they just rev away happily, but sometimes the noises can be a bit more sinister, which brings on the question: just what do those noises mean?

We know a thing or two about noisy engines here at Haynes, so if you’ll indulge us while we employ endless onomatopoeia, we’ll do our best to educate your ears.

The dull clunk

Sounds like: Hitting lump of wood with a hammer

This first one is probably the most common. Imagine hitting a solid lump of wood with a big hammer. It’s a dull, heavy sound with a soft edge. Not a sharp, snappy sound. In this instance, it will be irregular, too. Why? Because it’s sign you’ve got a worn out suspension bush somewhere.

The noise is created by metal parts being given more room to move due to the rubber gripping them becoming perished. You may notice it more when going over bumps, or when turning and shifting the weight of the car.

If that’s the case, you’re going to need to have the bushes replaced. Any garage can do this, and it’s not too big of a job. Just make sure you don’t ignore it. The rubber is there for a reason – metal suspension parts aren’t supposed to spend their time hitting other metal.

The droning whir

Sounds like: A lawnmower being used by your neighbour two doors down, but with a little bit more bass in the tone.

This one is also quite common. The noise will be a low down hum and will seem to have a fair bit of bass. The pitch of the hum, or drone if you prefer, will change depending on the vehicle’s speed. If you turn left or right, the noise will possibly go away completely for a moment or two.

What’s causing this then? That’ll be a collapsed wheel bearing. Within your wheel hubs, onto which the wheel is bolted, there is a small bearing that allows the wheel to spin freely.

Over time, these bearings wear out. That’s the noise you’re hearing – the bearing is no longer allowing the hub to spin freely. That noise is, quite frankly, friction. And on a part that’s meant to move smoothly, that’s a bad thing.

Happily, a new bearing should be under £40, and it’s an easy enough job for a garage to do, though if you have a hydraulic press at home, you can do it yourself, too.

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More noises your engine makes (and what they mean)

The tick tick tick

Sounds like: Well, like something going tick tick tick

This is an annoying noise, and one that could mean big bills if you ignore it. If you get a ticking noise, normally from the front of the car, there’s a good chance it means your constant velocity (CV) joint is worn. Normally packed with greased and protected from the elements by a rubber ‘boot’, the CV joint is a crucial part of driving your wheels. If you’re getting a ticking noise, it means it’s worn out.

A worn out CV joint will get hot, it will get progressively weaker and eventually, it will break, leaving you stranded in the process. Most garages can have a look and fit a replacement if needed, though be warned, it can be costly as it requires the removal of the brakes, wheel hub and even suspension parts in some cases.

The metallic grind

Sounds like: Metal grinding on metal

There’s a reason this noise sounds like metal grinding on metal. It’s because it is metal grinding on metal, and grinding metal has no place in a car, at least not one you’re trying to drive.

Annoyingly though, this noise doesn’t rank all that high on a decibel meter. Handily, there is another clue: you’ll feel this noise.

No, we’ve not gone mad. The noise is caused because your brake pads have worn out, and as such, the metal pad backing (onto which the braking compound would have been mounted) is now being pushed into your brake disk every time you press the pedal.

And when you press the pedal, you’ll feel the grinding through your foot. Also, the harder you press, the noisier it will be. A simple fix this – get new brakes fitted!

The dull knock

Sounds like: Hitting the bottom of a pan fully of mashed potatoes with a wooden spoon

Don’t ask us how we came up with that aural likeness. It just popped into our head. It’s also true, because a low-end engine knock will sound like that, what with the noise being muffled by the engine block and all the oil within. It’s a very distinct sound, and one that should you hear it, is a very good reason to stop the car immediately.

This is the big one. It means that something deep within your engine has broken or has worked itself loose on its way to breaking. Connecting rods, the big end or even the crank could be to blame. And as you can imagine, none are cheap to fix. However, you might completely write the car off if you persist with it, so stop and get it to a garage asap.