# What would cause damage to a flywheel?



## Tweetybird

Afreind of mine called and she and I got into a discussion regarding the flywheel. She apparently had had damage to the flywheel in her old van. She asked me, what could have caused the damage to the flywheel. I told her it was most likely broken teeth. Isn't the flywheel where the starter meshed with the engine, and the teeth is where the starter "grears' grab on to spin the flywheel to start the engine? What would cause the teeth to break, rough handling of starting the car, such as keeping the key turned even after the car has started? That is what I was thinking it was. Also, could small gravel flying up from the road get cought in the gears, and cause them to break when you attempt to start it? She was asking me these questions and thought this might be a good place to get an answer. Thanks in advance for your answers and thoughts.


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## rambler

Unless this is really, really old & has an inspection hole, they are all sealed - no gravel damage. A starter problem, that doesn't disengage or was held on would do it. Wear from just being old could cause pieces to break, causing more damage. Many are heat shrunk on, could warp or some such & be out of line & mess up?

--->Paul


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## agmantoo

Worn starter drive components, worn bushings in the starter, improper shimmed starters on vehicles that use shims, weak batteries and aged equipment cause flywheel problems. Most engines will stop in the same stop each time the engine is shutoff. That causes the same spot on the flywheel to be engaged each start. The clashing of the starter drive into the flywheel teeth over time will damage that section of the flywheels teeth.


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## haypoint

Vehicles with manual shift transmissions have flywheels. Automatic transmissions have flexplates. Both have ring gears around the outer edges. Both can get damaged gears from several starter problems and even ignition timing errors can cause damage to a flywheel if the engine "kicks" back. Flywheels can crack and score from the heat of a slipping clutch. Flex plates can crack for a number of reasons.


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## FreightTrain

the #1 cause IMO is by hitting the starter while the Eng is running.


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## wy_white_wolf

Just wondering as Haypoint pointed out about flywheels and flexplates. 

You say she has an old van. Most old vans that I know are automatic. Chevys (and others) have had a proplem of the centers of the flexplates cracking out. Caused by slight misalingment of the engine and transmission. The flexplate was invented to for that problem (hence the name) but many are built to weak and fail overtime.


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## Beeman

Many times theproblem is directly related to the human element of vehicle operation or repair.

Hitting the key while the vehicle is running is a cause. Not repairing a starter system that is showing signs of trouble can cause the problem. Any repairs done to the vehicle using poorly made or installed parts is a major cause. Replacement of the starter can be the cause as many replacement starters have poorly cast parts causing misalignment problems compounded by starters installed but not checked for proper gear alignment.


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