Why does my car make clunking and knocking noises?

There are several areas where a clunking or knocking noise can occur, and you shouldn't overlook any of them. The majority are warning signs—signals of worse and further destructive problems ahead.

Failure of components is often costly and could cause associated damage to other parts or areas of your vehicle’s operation. If you hear any clunking or knocking noises, it’s essential to locate the problem and get it sorted ASAP.

What are the common causes of clunking and knocking noises?

My engine is clunking and knocking

Risk level – High

What to do – Stop driving and have the engine checked immediately.

A knocking in your engine could be something as simple as a poor fuel mix. The wrong blend of fuel and air can cause multiple ignition points, creating those knocking noises you can hear. At the other end of the spectrum, it could be worn out or loose rod bearings, timing belt problems, or your engine preparing to seize.

Replacing or repairing an engine is one of the most costly repairs for any vehicle. In some cases, especially with older cars, when your engine seizes, it’s not worth repairing, and you’ll need to replace it. Don’t take any risks; have the car collected and towed to the garage.

Lesser issues (but still in need of attention) include low oil pressure, valve lifter failure, blockages in your emissions, or even bad timing. Poor fuel mix, failed sensors, and timing issues can be sorted with an engine diagnostic, where worn bearings, tensioners, and pulleys will need replacing as soon as possible.

I hear clunking and knocking while braking

Risk level – Medium

What to do – Have your brakes inspected for damage and wear immediately.

If your wheels are clunking and knocking under braking, then the problem could be with your callipers, wheel bearings, discs or pads. With so many possible problem areas, you’ll need a mechanic to locate the culprit part. Driving with faulty brakes is never advisable—as it’s dangerous! Get them fixed ASAP.

My car makes knocking noises when I start it

Risk level – Medium

What to do – Replace your starter motor.

There are a couple of reasons your car can clunk under starting, but the main one is that your starter motor is on its way out. Replacement is a fairly straightforward job but can be time-consuming. Failing to replace a faulty starter motor can lead to more serious issues with your engine—so don’t put it off—have it replaced straight away.

There are clunking noises when I drive over bumps

Risk level – Medium

What to do – Check all suspension components, steering column, and your exhaust system.

If you drive over bumps or potholes and you hear knocking noises from under your car, there’s a strong chance it’s your suspension or shock absorbers. The suspension consists of many parts, so have a mechanic isolate the issue. Also, the steering works hand-in-hand with the suspension, and in some instances, that’s where the problem lies.

Another reason could be that part of your exhaust system has come loose, a fixing bracket has broken, or two of the parts have come apart. However, if sections of the exhaust have separated, it’s likely that you’ll hear a lot more noise than a little clunking and knocking!

My wheels are clunking and knocking

Risk level – Medium

What to do – Check for bad ball joints, sway bar link, or tie rods.

These components are more parts of your suspension, connected to the wheels and steering. The ball joints connect the wheels to the suspension; the sway bar link (or anti-roll bar) prevents the car from tipping over around sharp bends, and tie rods connect the suspension to the steering. If any of them break or are damaged, you could hear all kinds of nasty knocking noises.

What should I do if my engine is clunking or knocking?

Given the range of reasons and the risks of driving with a clunking or knocking car engine, then we’d always recommend having your car examined immediately. Don’t take any risks; those noises could cause a serious failure, endangering you and your passengers, never mind the hefty costs of a big repair bill.

Is it safe to drive with a clunking noise?

Sometimes, as it depends on the problem—but is it worth the risk? Without knowing precisely what or where the noises are coming from and are caused by, you’re playing Russian Roulette with your engine, your passengers’ safety, and your finances!

Why is there a clunking noise when I accelerate?

Again, there could be a few reasons: worn engine components, low oil pressure, piston slap—none of them are great news. Or it could be an issue with your transmission or gears, failing wheel bearings or wheel hub. Whatever it is, it needs correcting before it breaks completely.

If your car is making any noises that it shouldn’t and causing concern, one of our trusted mechanics can visit you to locate the problem. Book in with Fixter, and we’ll run a diagnostic test or carry out a mechanical examination. Once we understand what the issue is, we’ll explain how we can fix it and what it will cost.