What Is the Grinding Noise When Starting a Car?

Starting a car includes a series of noises, but a loud grinding shouldn’t be a part of it. Here’s why.

A lot happens under the hood of a car when it starts up. The fuel pump sends fuel to the injectors, which spray fuel into the combustion chamber. The throttle body opens up to mix air with that fuel, and the spark plugs fire off in sequence to get each cylinder’s air/fuel mixture ignited, creating combustion. Finally, the starter is there to help get combustion going, as well as to begin pumping oil throughout the engine’s tiny cavities.

All of these make different, distinct noises, some of which can even be discerned from the driver's seat. But if instead of an engine firing to life, there’s a distinct grinding noise, there’s something wrong.

The Sounds of Startup

First, it’s important to dive into what is and what isn’t a healthy startup noise. 

• If a repeated click-click-click occurs, that’s indicative of an ignition system that’s doing its job. 
• If there’s a whirring noise, that means the starter is spinning the crankshaft—which pushes the pistons up and down—to prime the engine.
• If both of these noises occur, yet the engine doesn’t start, then there’s an issue related to air or fuel, which means the components that provide these aren’t doing their jobs.

On the flipside, if one of these noises is not present, that means the corresponding component isn’t working correctly. The most common is the lack of a click-click-click—this often follows with a shaking tachometer needle. The lack of sound means that the battery is dead, and that there’s no electricity coming from the battery to start the engine.

Grinding Should Never Occur

If a driver tries to turn the key in the ignition when the car is already running, the car will give off a horrible grinding noise. The noise is due to the flywheel, which is connected to the crankshaft and drives the crankshaft at startup. The engine’s idling RPM is much faster than what the starter spins at, so the starter will essentially be over-spun and create a loud, distinct noise.

However, if this noise is heard at startup, then there’s a problem. When the driver starts the car, the starter and flywheel (which is connected to the crankshaft) should be in sync and not make any kind of grinding sound.

The Root Cause of a Grinding Noise When Starting a Car

When there’s a distinct grinding noise at startup, it means there’s something wrong with the starter and its interior components. One of the key aspects of a starter’s operation is disengaging as soon as the engine has fired up. When that doesn’t occur, it means there’s a problem.

This usually doesn’t happen out of the blue, either. Early signs of a dying starter include slower-than-usual cranking or a louder-than-usual cranking noise. Drivers may also notice the whirr from the electric motor might sound more coarse and uneven.

Is a Grinding Noise an Expensive Proposition?

Once a starter grinds and doesn’t fire up the engine, it must be replaced. 

Luckily, replacing a starter isn’t a very labor-intensive job on most vehicles. It requires gaining access to where the engine and transmission meet, which for some cars is easy to access—thus, cutting down on the amount of labor involved—and starters are generally simple components that aren’t very expensive to buy. Though the total cost depends on several variables.

Generally speaking, the cost to replace a starter could range from $200 to $1,500, depending on the year, make, and model of the vehicle.

It’s also important to inspect the flywheel for damage when doing these kinds of repairs. If there was any resistance between the two components, that could mean the flywheel might possess some broken teeth. This would increase the repair bill quite a bit, as it takes more time to remove the transmission to access the flywheel.

Summary

It’s normal to hear some noises when starting a car. But if one of them is a loud, pronounced grinding, and the car doesn’t start, it means the starter is dead and must be replaced.

If there is a grinding noise present when the car does fire to life, and doesn’t cease shortly after, that could be a much more expensive issue. There’s a good chance that this is due to an oil-related problem, and the vehicle should be shut off immediately and towed to a professional shop for inspection as soon as possible.

The best way to avoid these kinds of issues is to ensure the car is in good mechanical shape, replace the battery and various ignition components in accordance with the manufacturer’s recommended service intervals, and pay attention to how the car sounds and feels every time the car comes to life.

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