3 Signs of a Bad Car Flywheel

A close-up of the car flywheel in a Honda Civic.

A car flywheel, simply put, is a mechanical device that can store rotational energy. It also helps reduce the vibration and keeps the gears working when the clutch is used. Thus, it is a very important part of the car, especially in manual transmission engines, and just like any other machine part, there will be times when the flywheel stops working properly. So, what are the signs that your engine's flywheel is damaged?

1. Gear Slippage

Gear slippage is the inability of the car to move to the next gear. The car may also shift to the next gear but slip back to the previous gear or increase speed slowly. This can be attributed to a bad flywheel, which causes plate grinding, amplified friction, and oil contamination. When these things happen, the inner machinery of the flywheel is prone to gear slippage.

A soft pedal and/or delay in engagement after the clutch releases are the most recognizable signs of gear slippage.

2. Burnt Smell

One of the major indicators of a bad car flywheel is a burning smell, like that of burnt toast. The burning odor is the effect of too much heat in the clutch facings, which is usually brought about by unnecessary clutch driving.

3. Clutch Vibrations

When you feel an intensified rumbling or vibration while you use the clutch, it can be a sign of a bad flywheel. Usually, these vibrations can be felt on the floor of the car, and they occur due to failure of the spring mount mechanism of the flywheel, which then leads to an inability to diminish the tremors as the driver uses the clutch.

Other Things to Look For

Besides these three major symptoms, there are still other symptoms that may indicate a problem, although they are not always a direct result of a flywheel failure.

You may experience some clutch drag, the opposite of slippage, wherein the clutch will fail to release properly. It can start as a mild grinding sound when shifting gears, but as it grows worse, you could have trouble engaging first gear upon starting. This phenomenon is sometimes caused by a failing pilot bearing or brushing in the flywheel, but it can also be produced by problems with the crankshaft assembly.

Clutch chattering can also be a sign of a damaged flywheel. Many causes of clutch chatter originate with the clutch disc, but grooves in the flywheel or missing or damaged dowel pins can be the source as well.

There are different types of flywheels for various makes and models of vehicles, but these symptoms will remain fairly universal. Damaged and faulty auto parts will eventually mean trouble for the rest of your vehicle’s machinery, so learn to recognize these signs and fix the problem early.