Mike Bewsey, the chairman of industry trade body the Verification of Lubricant Specifications (VLS), warns that using the latest engine oils in older customer vehicles can potentially be problematic.
The number of vehicles on UK roads is growing, but it’s also ageing. According to the latest European Automobile Manufacturers Association (ACEA) 2023 Vehicles in Use report, there are 36.7 million passenger cars on UK roads. Of these, 15.3 million are over a decade old, and the average passenger car age has risen to 10 years. In 2019, the average was eight-years-old, demonstrating a substantial increase. The economic impact of COVID-19, automotive supply chain issues, uncertainty about the future of internal combustion engine vehicles and the cost-of-living crisis mean that motorists are holding onto their vehicles for longer than ever. “On the one hand, this is good news for motor factors,” Mike Bewsey commented, before continuing:
More older vehicles on the roads means greater demand for servicing, repairs and MOTs, resulting in increased sales of consumables and parts for motor factors. However, as cars age, some aspects of servicing, such as supplying the right engine oil, can become more complex.
Engine technology has evolved significantly over recent years. To meet government requirements for reduced emissions and consumer needs for economy and performance, smaller engines are running at higher temperatures to maximise efficiency, power output and fuel economy. Longer oil drain intervals, taken together with smaller sumps and the need to minimise emissions, have created the need for less viscous, synthetic or semisynthetic oils to provide the lubrication required in these challenging conditions.
But these highly efficient, sometimes ultra-low viscosity lubricants are not always suitable for the ageing vehicles being serviced in workshops. The latest formulations are specifically developed for the most modern engines. Traditionally, when newer oils were developed, some were designed to be ‘backwards compatible’; however, with an increasingly complex range of industry and OEM specifications, backwards compatibility cannot be assumed. Subtle yet important differences concerning viscosity characteristics and/or additive chemistries are reflected in specifications that must be acknowledged during regular servicing.
Generally speaking, using the wrong oil risks accelerated wear, the formation of deposits, decreased fuel economy and damage to emission control devices. Left unchecked, it could lead to eventual engine failure, meaning higher maintenance costs for drivers, a potential rise in garage complaints and damage to business reputation. If a technician puts a low viscosity, low SAPS (Sulphated Ash, Phosphorous and Sulphur) oil in a vehicle requiring high levels of SAPS, it may not offer the wear protection required. The additives for a lower SAPS oil will differ as well. Additives help to provide the performance characteristics of an engine oil, but modern lubricants are designed to deliver performance through a thinner, less viscous oil that might not be suitable for older cars.
Workshops may also be tempted to find ways to offset rising costs by choosing cheaper oils. In this case, you have a vital role to play in educating technicians. The cheapest possible oil could be a full SAPS oil intended for older vehicles. This could have a negative impact on the exhaust emission system, poison the catalyst or block the diesel or gasoline particulate filters, reduce the overall efficiency and result in failure of the particulate filter or catalyst – both expensive to replace. Too much phosphorous from a high SAPS oil can also poison the selective catalyst reduction units designed to control nitrogen oxide emissions. Short-term gain may lead to long-term pain.
VLS strongly recommends both you and workshops use online databases to identify the correct oil for each and every vehicle. Looking beyond the viscosity to specific ACEA and OEM standards is essential. This ensures that the lubricant is fit for purpose in that specific vehicle. If there is still any uncertainty, it is best to get in touch with the OEM.
- A 2021 VW Polo 1.0 mpi requires an SAE 0W-20 engine oil complying with the latest VW 508.00 specification, part of which mandates very low high temperature, high shear properties (HTHS) to improve fuel efficiency
- HTHS measures the viscosity or resistance to flow of an engine lubricant at elevated temperatures under constant shear. This oil would be unsuitable for a 2017 VW Polo 1.0, which requires an SAE 5W-30 oil conforming to the older VW 504.00 specification, with higher and exclusively different HTHS properties
- Use of a VW 508.00 compliant engine oil in place of VW 504.00 would potentially result in accelerated wear of engine components
- In contrast, a VW 504.00 compliant engine oil instead of VW 508.00 would affect emissions and fuel economy
The VLS is an independent trade body that upholds standards in the lubricants industry by ensuring that lubricant products can deliver what they claim.
