Engine Oils And Lubricants. Engine Oil, 4 Litres, Castrol Available here. At MicksGarage.com we stock a huge range of engine oils, gearbox oils, ATF, brake fluids, coolants and antifreeze and all the other fluids and lubricants required to keep a modern car running smoothly (and old ones too!). If you're looking for the best engine oil brands such as Castrol, TOTAL, Mobil 1, Comma, KAST and many more, you're in the right place. When selecting the right oil for your car, don't assume that cheap engine oil will be poor quality. Also don't assume that the most expensive is the best engine oil. Choose the right spec oil for your car and change it regularly. Experts recommend you change your oil every 3000 miles. It's possible that you will need to top up your oil in-between services as well. To avoid paying high garage forecourt prices it's a good idea to keep a 1 lite top-up of oil in your boot. Using the engine oil finder will ensure you get the right spec oil for your car. Bear in mind that more than one grade of oil might be recommended. For example, 5w30 engine oil and 10w40 engine oil might be suitable for your car. The oil finder system also tells you how much oil your car needs and how often you need to change your oil.