Which Oil to Use

Which Oil to Use

Oil Viscosity – Which oil to choose?

When you need to top up your engine oil are you confused as to what oil to buy?

Visit any service station, automotive spares shop, even supermarkets and you are faced with dozens of brands and varieties to choose from – 5W-20, 5W-30, 10W-30, 10W-30 and more plus synthetics, mineral based ………….

New car owners should refer to their owner’s manual as a reference guide. Older car owners should ask their local service centre or repair shop what oil they use when they service your car, and for you DIY enthusiasts Caltex have a user friendly site at


Let’s get back to viscosity. Simply put this relates to the thickness of an oil and how easily it flows, for example, the thicker or higher viscosity (SAE) of an oil, the slower it will flow, so it follows the lower the viscosity the faster it will flow.

Using the correct oil to suit your particular engine and its environment is critical to the longevity and performance of your engine.

In Australia temperatures can vary from around – 0ºC up to + 40ºC.

Generally good quality multigrade oil will do the job however you should consider the following:

  • The age of your vehicle and how many kilometers its traveled
  • The type of use, local driving, long trips, carrying heavy loads
  • The environment, dry and dusty, cold, hot, wet, coastal, mountains

All of the above and more will have some effect on your vehicles performance, durability and fuel economy. Keep in mind a well maintained vehicle will give you the service you expect.

Consider that if you use thick oil it will take longer for the oil to reach its optimum operating temperature and do its job. On the other hand if the oil is too thin critical engine parts will not have sufficient oil protection under harsh operating conditions. Choose wisely and keep in mind that oil and filters are the cheapest form of maintenance.

Book your next service and protect your investment at Southport Car Service

Happy motoring!