Drivers urged to fill up on petrol before heatwave Met Office says will hit 34C

Drivers urged to fill up on petrol before heatwave Met Office says will hit 34C With another scorching heatwave on the way for parts of the UK next week, experts are warning drivers against a potentially costly mistake Drivers are being urged to fill up their tanks before another sweltering heatwave hits the UK next week. The heat can cause cars to burn fuel at a faster rate than usual, potentially catching motorists out, experts have said. The Met Office says that temperatures are expected to approach the low 30Cs at the beginning of the week before the heat surges and peaks with scorching highs of 34C possible in the South East on Thursay or Friday. Drivers may not be aware that such hot spells pose a risk to fuel levels. Petrol, or diesel, can run down at a faster rate than normal due to driver behaviour - like using air conditioning - and extreme heat can have an adverse impact on fuel economy. Fuel gauges can also become inaccurate and unreliable at conveying how much gas you have left in the tank, The Express reports According to the US government, driver behaviour that can increase fuel usage includes opening windows and using air conditioning. The US Department of Energy says: "Hot weather can increase fuel economy - the engine warms up to an efficient temperature faster; summer grades of gasoline can have slightly more energy; and warm air causes less aerodynamic drag than cold air. "However, keeping comfortable in hot weather by rolling down the windows or using the air conditioning (A/C) can reduce fuel economy. Running the vehicle's air conditioning is the main contributor to reduced fuel economy in hot weather. Its effect depends on a number of factors, such as the outside temperature, humidity, and intensity of the sun. "Under very hot conditions, A/C use can reduce a conventional vehicle's fuel economy by more than 25%, particularly on short trips. The A/C's effect on hybrids, plug-in hybrids, and electric vehicles (EVs) can be even larger on a percentage basis." Another reason to consider filling up in advance, is so drivers don't run the risk of becoming stranded in traffic in the heat. Experts at PassMeFast.co.uk said: “When it comes to topping up the petrol in your car, there are two kinds of people: those who refill as soon as the fuel tank gets to around a quarter full, and those who are happy to drive around with the fuel warning light on. “The thing is, when the weather's nice and warm, your car's fuel levels drop a lot quicker than usual. This means you can't rely on your normal estimations of how much time you have left before needing to fill up. “To avoid getting stuck in the middle of nowhere, or at the centre of a traffic jam on a hot day (both nightmare scenarios), make sure you head to the petrol station in good time. Playing it close to the line is just not worth it if the sun's out!” The warnings come as drivers in the past had been warned not to fill up their tank during hot weather due to risk of the vehicle 'exploding' in the sun. Fortunately, that isn't a genuine hazard and is, in fact, a myth. RAC spokesperson Rod Dennis said: "There is no truth in this. All fuel systems on passenger vehicles are designed to cope with any expansion of fuel, or vapour coming from the fuel. "There is no risk of explosion from filling up a fuel tank fully and drivers should have no concerns in doing so." When it comes to running the car as economically as possible, experts warn there is a sweet spot where performance is optimal between cold and hot weather. They say 20C is the ideal temperature for better fuel economy compared to cooler temperatures, but when the heat rises, the gains are lost again. Fuel Finder UK explains: "According to official fuel economy tests, your car's efficiency drops by around 10% at -5°C compared to 20°C. For short trips under four miles, that penalty can reach 20% or more." According to Fuel Finder, the ideal range for fuel economy sits between 15C and 20C, but when temperatures hit 32C, engine performance deceases and the chances of overheating becomes a risk.