How to spot a bad used car during a test drive – 4 Red flags to look out for

{RED FLAG 1} Engine knocking

The engine should start easily, idle smoothly, and respond cleanly when you accelerate hard. Make sure there is no engine knocking. Engine knock is a severe mechanical problem and it happens when fuel inside the engine explodes at the wrong time or worn metal parts bash into each other. Unlike normal engine humming, knocking sounds like metal parts striking each other, like coins rattling in a tin can. A fast, rhythmic metallic tapping or pinging coming right from the engine, which speeds up as you go faster. If you hear this sound, walk away from the car immediately.

{RED FLAG 2} Clutch bite

In a manual car, pay attention to the clutch bite point. The clutch bite point is the exact place where the engine connects to the wheels and you feel the car shake slightly and move forward slowly. It usually happens when your foot is lifted halfway up the clutch pedal. A high clutch biting point means the car starts to move only when your foot is near the top of the clutch pedal's upward travel and you are about to let go of the clutch completely. In a healthy clutch system, engagement happens around the middle. A high clutch biting point indicates that the clutch is pretty worn out and will need replacing soon. Also watch for engine revs increasing without a matching increase in vehicle speed, which is also a sign that the clutch is worn. A high bite point warns you that a costly clutch repair job could be right around the corner.

Clutch replacement cost

The part itself is cheap, but the clutch is buried deep inside the car. A mechanic has to take apart half the vehicle just to reach it, because this teardown takes so much time and effort, the labour charges make up most of your bill. Since the mechanic has already opened up the car, they have to replace the whole clutch system, not just the worn part because paying a mechanic to open the car up for a second time is simply too expensive.

{RED FLAG 3} Brake pedal feedback

Observe how the brake pedal feels when driving at low speeds. If the pedal feels spongy that is a red flag. It could be caused by air trapped in the brake system or just old brake fluid which are not expensive repairs and can be easy and cheap to fix, but it could also be caused by a failing brake master cylinder. The brake master cylinder is a pump that converts the force you apply on the brake pedal into hydraulic pressure. If it can't build pressure properly, your brakes can't deliver their full stopping power. A soft or spongy brake pedal is a warning sign that the braking system needs to be properly inspected before buying the car, because some of these problems are inexpensive to fix (such as bleeding the brakes and replacing the fluid), while others can be much more costly (replacing brake master cylinder). Without a proper inspection, you don't know which problem you are dealing with.

Identifying spongy brakes

Think about how your clutch pedal feels, it has a long, smooth travel. Your brake pedal shouldn't feel like that. A healthy brake pedal should feel firm and predictable. As you press it, it should quickly become solid and the car should respond immediately. If the pedal feels soft, squishy, or sinks to the floor while braking then that's what's meant by a "spongy" brake pedal. It is a red flag because even if the car seems to stop normally during a short test drive, a spongy brake pedal means:

• The brakes may require more effort and distance to stop.
• The problem could get worse over time.
• It also suggests the previous owner may not have maintained the car well.
• Most importantly it is a potential safety issue, so it deserves a professional inspection before purchase.

{RED FLAG 4} Steering feedback

While driving on a straight road, loosen your grip on the steering wheel (don’t completely let go). If the car constantly pulls to one side, don't ignore it. It could be something simple like wheel alignment or something more serious like worn out suspension or steering components. Next pay attention to what happens when you move the steering left and right, if you can move the steering wheel noticeably before the car reacts that could be indicate worn steering components (possibly the steering rack, tie rods) and these are more serious and much more expensive than a wheel alignment. For the last test you want to be in a safe open place or empty parking lot and you want to turn the wheel all the way to the left till you can’t turn it anymore. Now roll down your windows and drive around in a circle (with steering at full left lock) and listen. If you hear any abnormal noises like clicking (worn cv joints), squeaking (worn out ball joint or tie rod) and whining (power steering), it is a major red flag and a wheel alignment will not fix any of these issues. Ideally you want the steering to turn easily with no noises. Now once you completed turning left, you want to do the same turning right and feel and listen again.

It's very important to note that if worn steering or suspension parts are causing the problem, a wheel alignment won't fix it. This is because mechanics usually inspect the steering and suspension before performing a wheel alignment on a vehicle. If they find worn tie rods, ball joints, or other worn-out parts, they'll often recommend repairing those first because the alignment won't hold if you do it with these worn-out parts.