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How do I know my starter motor is faulty?

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Updated 12 Oct 2019

Denis Doherty

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A car engine is what is known as a feedback system - a system that essentially uses the momentum from one part of the engine's phase to ignite the second part.

This means once the engine has started, the gas and air mixture in one set of cylinders ignites, pushing those cylinders down and drawing another mix of gas/air in and the cycle continues.

The starter motor is what gets all this moving and it is just a powerful electric motor.

When you turn your key in the ignition, the car battery kicks the starter motor into life.

One end of the starter motor connects to a flywheel which spins, and that rotation turns the motor over, drawing in air.

A quick jolt of electricity to the spark plugs and, voila, your car has started and the feedback system kicks in.

The starter motor has done its job.

How do you know if your starter motor is bad and what are the symptoms?

There are only a few things you need to look for.

When you turn the key, does it start, or do you hear a clicking sound when you try to fire things up?

Either could point to your starter motor.

Try turning your interior lights and your headlights on and off.

If they're working, that could eliminate a flat battery as the source of the problem.

How quickly does your car start?

If there's a wait for the engine to tick over or the motor seems to struggle, that could be your starter motor.

Finally, is there a grinding noise when you turn your key?

Starter motors have gears and, when they start to wear out, they fail to grip, causing this grinding noise.

It's the same noise you hear if you hold your ignition key on start for too long.

What can cause a starter motor to burn out?

The most likely reason is that it remains engaged with the flywheel after the motor has started.

That can be caused by user error (people leave the ignition key turned to start for too long) or by a fault in the ignition system itself.

How do you start a car with a bad starter motor?

If you are desperate, there are some tricks you could try.

First, try a jump start - sometimes the starter just needs a nice dose of good old electricity to get going.

You could also try a push start.

Push the clutch in, put the stick in second gear, have a (very) good friend or two push the car and, when you are up to a decent speed, let the clutch out.

Finally - and unless you are confident around cars, we wouldn't recommend these - you could try the following:

  1. Look for signs of corrosion. Corrosion is the natural predator of electricity, so chip away and clean corrosion around terminals and connections.
  2. Check the starter motor’s earthing connection. Connect a jump wire from the negative terminal of the battery to the starter motor casing. If an earth wire is the problem, this should fix it.

These are temporary solutions, of course, and you should go to a mechanic to get things checked.

How long does it take to replace a starter motor?

That will depend on your car, but between two to four hours should cover it.

How much should it cost to replace a starter motor?

You can get new motors for around $200, but budget for between $400 and $600. 

For more info on how much a starter motor could cost, or to book your car in with a high quality, local mechanic, visit AutoGuru.  

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Written By

Denis Doherty

Denis Doherty learned to drive manuals when his dad took him out on flood-ravaged north-west Queensland roads and put him behind the wheel of the company's Toyota Land Cruiser.

Since then, he has loved cars and the freedom they offer.

Despite knowing better, his first car was a Mitsubishi Sigma, but at least it was the GLX which was modified by motoring writer Peter Wherrett.

He currently drives a 1998 Holden Calais but still wishes he was in his Peugeot 206 GTI180.