Electrical gremlins are the faults most likely to appear as a new car exits its standard three-year manufacturer’s warranty period, says Reliability Index.

The Reliability Index is run by Warranty Direct, providers of direct consumer warranty cover.  Based on data gathered from millions of pounds worth of claims handled by Warranty Direct every year, it provides information on the sort of costs you can expect with your car, how frequently it might go wrong and which parts you should expect to go wrong.

While some car makers offer longer new car warranties, sometimes of up to seven years, most still offer the typical three years’ worth of cover. Just over a quarter of cars suffer an electrical breakdown in their fourth year on the road, but axle and suspension faults have the sharpest increase between a car’s third and fourth year, jumping up nearly 4% to just over one in five (22%).

Engine failures are the third most likely thing to go wrong as a car comes out of the protective umbrella offered by a three-year manufacturer warranty, with 17% suffering a fault.

Over the last five years, air con and electrical faults are the failures that have consistently increased as soon as a car enters its fourth year.

Data analysed from the 30,000 Warranty Direct policies showed that electrical and engine faults are actually more likely in a three-year old car. But the repair bill for an engine failure on a four-year old car is considerably more expensive, at an average of £740.76 as opposed to £692.26 on a three-year old vehicle.

Gearbox faults are the most expensive to fix on a four-year old car, with an average repair bill of £896.22, more than a hundred pounds more than on a three-year old car.

The cost of fixing steering system woes also jumps between a car’s third and fourth years, again by more than £100, to an average of £532.37.

Warranty Direct summarised that overall, the average repair cost for a four-year old car is £480.74.

For more information on the reliability of your vehicle, visit the Reliability Index here