What are the symptoms of a bad car camshaft?
3 Answers
The symptoms of a bad car camshaft are: 1. The car accelerates weakly and cannot run properly, with slightly better performance when the engine speed exceeds 2500 RPM; 2. The car will exhibit high fuel consumption, excessive exhaust emissions, and unpleasant black smoke from the exhaust pipe; 3. The engine fault light will illuminate after detecting a sensor malfunction, reminding the owner to inspect and repair; 4. The car idles unevenly with severe shaking, similar to a cylinder misfire; 5. During the starting process, there will be a phenomenon of crankshaft reversal, and backfire may occur in the intake manifold. The camshaft is a component in a piston engine, responsible for controlling the opening and closing of the valves. Although in a four-stroke engine, the camshaft's speed is half that of the crankshaft, it typically still operates at high speeds and needs to withstand significant torque.
I've been driving for so many years and have encountered camshaft issues several times, which is quite frustrating. The most common problem is when the engine suddenly starts shaking violently, making the whole car vibrate, especially noticeable at low speeds or when idling at a stoplight. Another frequent issue is the lack of power during acceleration - stepping on the gas feels like the car hasn't woken up yet, moving sluggishly with even more difficulty going uphill. A major red flag is strange knocking sounds, like metallic clicking noises, particularly audible in the engine compartment. Sometimes the car has trouble starting, requiring multiple key turns before it fires up, with unstable RPM fluctuations at idle. If these problems aren't fixed early, they can damage other components like valves or timing chains, leading to more expensive and complicated repairs later.
I usually drive to and from work, and the experience when the camshaft fails is extremely annoying. The car suddenly loses power, feels sluggish when accelerating, making it impossible to speed up, and even safe overtaking becomes a problem. Noise is also a big signal—the engine makes strange clunking sounds, and when stopped at a red light, the whole car shakes, like sitting on a massage chair but with zero comfort. If the idle is unstable, the tachometer jumps around or fluctuates wildly, and you can feel the car acting up even when stationary, especially when the AC is on in summer. If this problem drags on, fuel consumption increases, a full tank doesn’t get you far, and your wallet suffers too. Regular checks are important—just listening to the engine’s sounds can usually hint at the issue.
