“Oh no! The head gasket has gone!” Uttering such a sentence means motorists could be facing a four figure bill to get their car back on the road.

And amid the current cost of living crisis, the last thing that cash-strapped drivers need is an expensive garage bill which could cost hundreds of pounds or even more than £1,000 when something goes wrong on their car.

The experts at LeaseCar.uk have compiled seven of the most common car parts which need replacing and why, through online search trends.

A spokesman for LeaseCar.uk said: “There is little worse than going about your day on a car journey only for something to go drastically wrong and lead to an unexpected breakdown.

“Drivers with mechanical knowledge might know instantly what has stopped working but for many it is impossible to tell what has occurred under the bonnet until they take it to a garage.

“Regular servicing can help keep an eye out for signs of wear and tear and deterioration, but the simple fact is most of us don’t have lots of spare money for expensive car repairs, so it is useful to know what are the most likely – and expensive car parts that can go wrong.”

It’s not just the car part itself that can prove costly – there is also labour to factor in and the potential for other car problems to be uncovered at the garage. Ensuring you take note of advisory guidance as part of your MOT can help pre-empt problems too, as well as keeping your vehicle’s oil, lubricant and water levels healthy at all times.

Here are LeaseCar.uk’s guide to the most common and expensive car parts that might need changing:
Head gasket – the role of the head gasket is to keep the combustion chambers, oil and cooling systems separate. If it fails, it can lead to some dramatic symptoms such as blue smoke coming from the exhaust and the potential for oil and water to get into the cylinders. The cost is less about the car part itself, but the labour and skill needed to replace it as it is quite a complex mechanical process.
Clutch – learner drivers are often told to avoid getting into bad habits such as ‘riding the clutch’ when they are on the road as it can cause unnecessary wear and tear. It can cost more than £1,000 for a clutch assembly replacement, but in view of the huge amount of gear changing that goes on in the life of a manual car, this cost can often be anticipated after a certain amount of miles driven.
ECU replacement – with so much of our modern day cars relying on electronic systems – be it for windows, temperature control or other things, one item you want to be reliable at all times is the ECU (Engine Control Unit). This can provide a steep and unexpected bill to pay if this goes wrong in the car, and while designed and manufactured to last for years, like anything, they can go wrong.
Catalytic converter – this can cost a huge amount to replace, as it contains specialist materials such as palladium, rhodium and gold. While designed to carry on working throughout the car’s life, if it goes wrong and needs replacing you are facing a hefty bill.
Timing belt – Often people are advised to replace this car part by a mechanic during a routine check, even though it may appear to be working perfectly fine. It is critical to the smooth running of the vehicle, connecting the crankshaft in the base of the engine with the camshaft in the top, but if it begins to slip, can cause internal and expensive damage to the engine.
Starter motor – if you start your car and the ignition doesn’t work, it is common to assume that you might have a flat battery, especially if the car has been standing for a while. However, on closer inspection at the garage, once the car has been transported there, could determine a more expensive repair is needed if instead it is a faulty starter motor.
Alternator – if you do a lot of mileage, then one of the most common expensive car parts which can fail after racking up thousands of miles is the alternator. If it gives up the ghost, it means the car’s entire electrical system also fails, and will cost a motorist a four figure sum to replace, unless they opt for a cheaper used alternator instead.