What are the symptoms of a damaged flywheel?
2 Answers
When the car's flywheel is damaged, it will cause the engine to produce abnormal noises during operation, accompanied by noticeable shaking, and can also lead to an imbalance in the transmission shaft of the gearbox. The car flywheel is a disc-shaped component with a large moment of inertia, functioning like an energy storage device. Since the power strokes of the engine cylinders are not continuous, the engine speed fluctuates. When the engine speed increases, the flywheel's kinetic energy increases, storing energy. When the engine speed decreases, the flywheel's kinetic energy decreases, releasing the stored energy. The flywheel helps reduce speed fluctuations during engine operation. The car flywheel is mounted at the rear end of the engine crankshaft. Through the clutch installed on the flywheel, it connects the engine to the car's transmission system and engages with the starter motor to facilitate engine starting. It also serves as the integration point for the crankshaft position sensor and vehicle speed sensor. Methods to determine flywheel damage: Check if the starter ring gear on the flywheel is intact. If the ring gear shows significant wear at the tooth ends or broken teeth, the starter ring gear or flywheel needs replacement. Inspect the flywheel surface for severe burns, impact marks, or scratches. If such damage is present, the flywheel also requires replacement. Measure the wear depth of the grooves. If it exceeds 0.5mm, the flywheel is damaged and needs replacement.
Having driven a manual transmission car for over a decade, I know how unpleasant it is when the flywheel acts up. At first, you just hear this grating noise during startup, like a friction sound warning you not to ignore it. Gradually, the engine becomes unbalanced, with noticeably increased vibrations at idle—the whole steering wheel shakes, sometimes making it hard to even shift gears. If this feeling worsens while driving, especially when going uphill or accelerating, and the engine starts jerking, it’s likely the flywheel is worn or cracked. If not fixed promptly, the clutch could also get damaged. My advice: the moment you notice these signs, pull over and check immediately. Don’t wait for it to get worse—this is about driving safety. Getting a professional auto shop to replace the flywheel can save you a lot of money.
