Mistakes are still being made when it comes to oil choice and stocking policy by both factors and workshops according to a recent study.

The UK division of lubricant supplier Castrol carried out the study that showed that there is a discrepancy in the aftermarket between the oils available from workshops and retailers and the actual oils required according to latest car parc data.

Castrol say that 55% of the car parc requires low-viscosity oil, with 36% needing 5W-30 and 19% requiring fully-synthetic 5W-40. Despite this the study found that only 29% of retailers stocked 5W-30 oil with a mere 7% keeping the fully synthetic version.

Marc Perkins, Castrol Independent Workshop Marketing Manager for UK and Ireland, says, “The current trend for engine downsizing means that workshops and retailers must catch up in the marketplace and provide low viscosity oil formulations that are approved for an increasing proportion of the modern engines.” He added, “By continuing to offer only 10W-40 oil, or other high viscosity formulations, outlets run the risk of invalidating a vehicle’s warranty and ultimately harming the longevity of an engine, simply by topping it with the wrong type of oil. The growing demand for ultra low viscosity oils also offers workshops the opportunity to earn premium profits.”