10w40 vs 5w40 engine oil UK - what's the difference?

The main difference between 10w40 and 5w40 engine oil in the UK is their cold temperature performance: 10w40 can handle temperatures down to -25°C while 5w40 works in temperatures as low as -30°C. Engine oil serves multiple vital functions for your car: reducing friction and heat, cooling engine components, cleaning internal parts, cushioning impacts, and preventing rust and corrosion. For UK drivers with popular models like the Ford Focus or Vauxhall Corsa, proper oil changes are essential. To change your oil: 1) Safely lift the vehicle and remove the undertray, placing a 10-litre container under the drain plug; 2) Remove the drain plug and use compressed air at the filler neck for 2 minutes to ensure complete drainage before reinserting the plug; 3) Refit the undertray, lower the car, and carefully add fresh oil using a funnel. Always check for leaks afterwards. The lower winter rating (5w vs 10w) makes 5w40 more suitable for UK winters, particularly in Scotland or northern regions where temperatures frequently drop below freezing.