I’m a mechanic – here’s exactly how much you should fill up your car’s petrol tank in hot weather to save cash

A MECHANIC has revealed how much you should fill up your car's tank in hot weather - and it is less than you might think.

Experts at Bristol Street Motors shared a list of handy tips to help your vehicle beat the heat.

As the UK heatwave rolls on with the mercury set to hit 32C tomorrow, drivers should be aware that high temperatures can seriously affect their motors.

In terms of fuel, many may not know that it can actually cost them big at the pumps.

Petrol evaporates more quickly when it's hot which can mean you lose out on a full tank.

Likewise, as the heat ramps up, motorists are more likely to crank up the aircon or drive with the windows down, both of which can harm fuel economy.

In practice this means that a £50 top-up could only work out to £46-worth of performance, losing your £4 on each fill.

If you are someone who uses your car a lot or you leave it sitting in the sunshine for extended periods, this can begin to mount up to a major hit in the pocket.

Instead, the experts recommended only filling your tank halfway to ease the issue.

While it does mean more frequent trips to the forecourt, it will improve fuel efficiency and reduce the amount of petrol lost to evaporation.

It also saves you time and allows you to get back on the road and crack on with your journey.

Other hot weather tips included keeping engine coolant topped up, making sure your battery is charged and keeping up to date with normal maintenance jobs.

This is particularly important for fluids like engine oil and brake fluid, which also evaporate more quickly when it's hot.

It comes after drivers were issued a warning amid fears of a spike in breakdowns due to the weather.

Meanwhile, a car expert revealed why vehicles often look dirtier in the summer.