‘I’m a mechanic - one key sign that a £750 car part could be broken’

Top car mechanic Scotty Kilmer has revealed one simple problem that could suggest a major petrol and diesel car part is close to failing.

Dim headlights when setting off from a drive or while sitting in traffic could suggest a problem with the car’s alternator - one of the most important parts of the battery. An alternator is responsible for charging up a battery but a failure could see batteries quickly become drained. In time, batteries will run out of charge and road users will not be able to turn on their engine. Alternators can be pretty expensive with some motorists set to pay over £700 to get the part replaced.

Speaking on his YouTube channel, Scotty said: "If you’re headlights are getting dim when you come to an idle but then when you take off they get bright, here’s what’s often gone wrong.

"When your car is idling, the alternator spins slower. It's supposed to still charge but when they start to wear out, at low speeds they won't.

"So if both headlights are dim, get your alternator tested at any auto parts store to see if it's bad.

"But if only one of your headlights is dim, that's a problem with your headlights, so just try a new bulb. That should fix it if one side’s dull and one side’s bright."

Motoring repair experts at Halfords explained that flickering, dim, or unusually bright interior and exterior lights is one of the most common signs of an alternator failure.

They stressed on average alternators tend to last for between 80,000 to 150,000 miles before they need to be replaced.

The costs of getting a new component can dramatically vary depending on the make and model.

According to Bumper.co, alternator replacement in the UK will set drivers back between £250 and £750.

Breakdown experts at the RAC said: "The average price for parts and labour is around £525.

"It is worth noting that alternators can be one of the more expensive parts of vehicle to fix or replace."

However, the part is a simple fix and should take between an hour or two and a half hours for garages to complete the work.