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Oil changes and modern specifications

The consequences of slipping up…

Although performing oil changes is reasonably elementary, the lubricant itself is immensely complex. Therefore, Rob Marshall looks into the latest developments affecting the engine lubrication market and the consequences of technicians not keeping up-to-date.

While the main engine oil functions are well-understood by technicians, it is still quite magical that they maintain their cooling and lubrication properties within the environments of low viscosities, higher temperatures and extended drain intervals. Yet, the oil’s protective properties extend beyond the power unit. Certain anti-wear additives may be life saviours for the engine but they can be fatal for the catalytic converter, or DPF. As an example, Lucas Oil blends its engine oil in 10w-30, 10w-40 & 20w-50 viscosities, which contain high levels of zinc, molybdenum, and phosphorus to offer maximum engine protection for muscle, showroom, classic and trophy cars. As Lucas Oil admits, these formulations are more specialised applications, making them unsuitable for modern vehicles equipped with catalytic converters, or DPFs. In addition, some of the latest engines may be prone to specific issues, such as intake coking, and the car manufacturer may specify a particular engine oil additive formulation to minimise the effect. These are reasons why engine oil has become increasingly bespoke and why both owners and technicians have to be sure that they make the right choice.

Consequences of owner neglect…

Many technicians remain surprised about how badly certain owners neglect their cars, many of whom cannot even be bothered to check their levels. Even oil companies are trying to communicate this to the public. As an example, Castrol’s Oil Check Challenge seeks to raise awareness and encourage workshop visits.

Getting the oil right is not easy for newer vehicles. Prioritise manufacturer specifications over viscosity and API/ACEA ratings.

Deteriorated oil produces a sludgy deposit that can cause blockages. Should the crankcase breather be restricted, the crankcase can pressurise and cause oil leaks.

While physical oil leaks are certainly not intentional, all engines burn oil – although some of them do so more than others. Morris Lubricants explains that oil consumption is not necessarily a sign of excessive wear; it tends to be a consequence of efficiency technologies. An example is a relatively recent piston design, where the ring packs are moved closer to the crown to enhance swirl and optimise fuel and air mixing prior to combustion. However, moving the uppermost ring further up the piston exposes it to higher temperatures, but it still requires lubricating. This is a popular area in which oil is burnt. Millers concurs, stating that some manufacturers maintain that oil consumption should be expected.

Morris Lubricants adds that, should the owner not replenish the lost lubricant and the level falls, the remaining sump content faces increased stress and premature deterioration. The result is accelerated engine wear, poor engine cleanliness, corrosion and, possibly, overheating. The latter point is relevant, because oil has a major influence on crankcase temperatures. Millers explains that, should the level fall to the minimum allowed quantity, the remaining oil would have to work harder and, therefore, suffer a reduction in its lifespan and require draining sooner.

Aside from low oil levels, neglected oil change intervals present further problems. MOTUL reminds us that engine oils are formulated with set drain intervals in mind, because the additive packs are consumed over time. In addition, the engine oil becomes polluted by metals and solid dirt particles, unburned fuel and moisture. Therefore, it is logical that the consequences of neglected oil changes include enhanced wear and tear, corrosion and deposits accumulations, including sludge. The VLS adds also that the increased viscosity can raise fuel consumption and exhaust emissions.

Importantly, Motul emphasises that OEM handbooks state oil change intervals should be reduced according to operating conditions. As AT detailed in our 2020/1 lockdown editorials, multiple short journeys are tough on oil, not only because of the extra contaminations that it must suspend and extra acids that require neutralising, but also due to it not reaching its optimum operating temperature. Due to the oil deteriorating faster under these low-mileage conditions, you should insist that it is drained at least once annually. As many active DPF regeneration algorithms consider oil quality, neglecting drain intervals can cause aborted active cycles and, therefore, particulate blockages. The DPF Doctor, Darren Darling, finds that not resetting the on-board indicator post-service on some vehicles can hinder successful regeneration, because the car thinks that the sump’s contents is older than it really is.

Why ‘That’ll do’, won’t…

According to Euro Car Parts, technicians will turn often to a ‘one size fits all’ solution, such as stocking a 5w-30 C3 engine oil, theorising incorrectly that it can be used in most cars. Yet, a handful of engine lubricants will not suffice for every vehicle that enters your workshop. Selecting the correct engine oil requires additional research and the selection process has matured, too. Motul highlights that the viscosity grade is not a quality indicator; the correct marker is the OEM specification. Especially on turbocharged GDI models, low-speed pre-ignition (LSPI) is a continuing challenge and both Morris Lubricants and Motul highlight this engine-killing phenomenon as one reason that justifies the importance of choosing oil by prioritising OEM approvals, because a major contributor to LSPI is a calcium anti-wear additive contained within the oil. Yet, LSPI is not the only issue that is promoted by engine oil. Intake coking is another example, caused not by calcium but by viscosity improvers. OEMs will, therefore, formulate engine oils to reduce these issues as much as possible. Should garages choose to use the wrong oil, then the rate at which these issues occur will increase.

Choosing engine oils for modern applications starts neither with the viscosity, nor whether the lubricant is mineral, part, or fully synthetic. Checking whether, or not, the lubricant meets the car maker’s specification for that model must be the priority. Yet, should you be working on a classic model with no manufacturer recommendation, then the aforementioned specifications have more relevance. AT plans to investigate lubricants for historic vehicles in a future issue.


We are grateful to the Verification of Lubrication Specifications, the independent UK organisation that ensures claims made by oil companies are true, for informing us of the most up-to-date changes. While many aftermarket garages are unlikely to be affected immediately by the most recent developments, forewarned is forearmed…

The European Automobile Manufacturers’ Association (ACEA) has announced its 2021 sequences for light duty vehicles, catching-up finally with the American Petroleum Institute (API). The latest sequences can be claimed alongside the ACEA 2016 light-duty engine oil categories until next year. The new standards seek to address the challenges posed by the latest engine developments. Yet, the VLS comments that they represent evolution, rather than revolution.

Since AT covered this topic last year, the sequences tackle some of the existing technical challenges. These include new A7/B7 and C6 categories that address the impact of Low-Speed Pre-Ignition (LSPI) that affects turbocharged GDI engines primarily. Yet, it is worth noting that the ACEA sequences for heavy-duty diesel engines has been delayed, although the release of which is expected by the end of the year.

Interestingly, the introduction of new engine tests modernises the sequences to consider lower viscosity (i.e. thinner) lubricants, used in some of the newest engine designs. The VLS theorises that, given the transition of passenger cars and even light commercial vehicles to electrification, the ACEA engine oil sequences for light-duty engine oil will not be updated so frequently in future.

In terms of enforcement, the most common issues that the VLS encounters involve oil blenders over-claiming. This takes several forms – one of which involves companies claiming to meet certain specifications on their engine oil packaging but lacking any supporting evidence, when challenged. A further issue involves some products stating incorrectly that they are ‘officially approved’ by an OEM.

Should you be uncertain that claims, made by your oil blender(s), are untrue, you can request that the VLS investigates, by contacting it on 01442 875922 or visiting


As we are told that oil packs for modern engines are so carefully balanced, one would have thought that topping- up the additive packs would upset the chemistry. This appears not to be the case entirely but much depends on your aim. Opinions, therefore, differ. Motul told AT that using an ‘on-top’ additive generally can have a negative impact. The company reasons that all components within the oil formulation, the additives particularly, are balanced, which can be prejudiced by an unknown additive. Increased wear and tear, corrosion, deposits, accelerated oxidation and a viscosity increase can be the consequences. It also adds that you risk prejudicing the OEM warranty, by using them.

Meanwhile, BG Products views that, despite becoming ever more bespoke, engine oils are still formulated to a set budget and specification, meaning that oil producers have to balance price with top performance in normal operating conditions. Where ‘severe’ conditions are encountered, BG Products reasons that it provides customers with a choice to upgrade the oil with an additive package. As mentioned earlier, much depends on what you wish to achieve. Engine oil that is subjected to the severe conditions of not being able to reach its optimum temperature constantly may well benefit from extra detergents, for instance. BG Products also highlights that higher oil temperatures, such as those experienced with high-speed motorway driving, can also break down the engine oil faster and so extra fortification can be of use to help it retain its stability.

JLM Lubricants also offers garages the chance to upsell. Aside from its cleaning functions, the company told AT that its Bortec additive performs particularly well in areas of the engine subject to high temperatures, pressures and friction. In addition, the antioxidant in boron provides the engine oil with better protection against ageing, enabling it to maintain optimal performance for longer. JLM Lubricants insists that, since Bortec is based upon low viscosity base oil and, since a treatment consists of approximately 250ml, it is compatible with modern, low viscosity engine lubricants. This may not be the case for a relatively thick ‘stop smoke’ type of additive, however. As with any professional product, BG Products reminds us not to overdose, commenting that adding more than the recommended dose of a “top-treat” oil fortifier risks unbalancing the oil which can destabilise it.

Hailing from North America but available in the UK, Lucas Oil is another well-established quality brand that sells a variety of engine oil treatments but, again, much depends on the application. It reasons that engine oil additives are especially important in today’s engines that are smaller and more powerful than those of the past, which stresses vital engine components and the oil that protects them. One of its best-known products is the Heavy Duty Oil Stabiliser, which has been updated for today’s low viscosity engine oils, even up to 0w-8. While enhanced dispersancy and oxidisation resistance are advantages, Lucas Oil highlights that it is not lost focus on dry-start protection, which remains the primary cause of wear.


Morris Lubricants views engine flush additives as especially useful in scenarios where the vehicle possesses an unknown service history, the incorrect oil has been used, or the sump is contaminated by another engine fluid. Motul emphasises that lubricants, exposed to extended oil drain intervals, while operating under severe conditions, can be overwhelmed by solid and liquid contaminations. Consequently, these deposits can remain within the crankcase after draining, which will impact the detergency and dispersancy performance of the fresh oil. A flush, therefore, is beneficial. JLM lubricants agrees, stating that its Engine Oil Flush Pro is formulated to dissolve old oil residues and accumulated dirt in the lubrication system, plus the cylinder walls, pistons, piston rings, valves, guides and the combustion chamber. The net advantage is that it extends the new oil’s lifespan. Using such flushes, including Motul’s ‘Engine Clean’, Millers ‘Engine Oil Flush’ and BG Product’s ‘EPR’, also help to clean and free the low-tension piston rings, used most commonly in GDI applications. This helps to restore compression, therefore minimising the quantity of unburnt fuel entering the crankcase, which has the extra advantage of not degrading the engine oil prematurely.


While this feature focusses on engine lubricant and supplementary products, customers are querying garages about whether they should use E10 95 RON petrol with an additive, or the more expensive Super Unleaded E5 97+ RON grade.

To summarise, E10 petrol presents several technical challenges over E5. The extra ethanol corrodes certain metals faster. It also attacks the structure of certain plastics and rubbers. Even if the car’s fuel system does not contain such materials, it cannot escape other complications. E10 petrol absorbs moisture more readily, which tends to originate from condensation in the petrol tank. This incombustible ethanol/moisture mix then phase-separates from the fossil-fuel element and falls to the bottom of the tank. This leaves fuel above it with an octane rating below 95RON. E10 also oxidises, becomes more acidic and, therefore, ages faster than E5. Yet, even when fresh, E10 is an effective solvent, which risks fuel system blockages – further details about which can be found in our separate filtration editorial. For more information on E10, AT’s previous analysis on the topic can be accessed here:

You and your customers may have come across various fuel additives that claim to combat the negative effects of ethanol. Yet, as E10 presents several separate technical challenges, we questioned various additive producers about how their products could address them all. Unfortunately, some companies did not answer our questions; others revealed that their products only addressed certain issues and not others. At this point, therefore, AT’s examination of E10 fuel additives is inconclusive, meaning that we cannot make any firm recommendations at this stage.

Should you be queried by an unsure customer about E10, you can advise that the fuel can be used if the motorcar in question is both materially compatible (which can be verified by this link ) AND the driver fills the tank at least once every six weeks. Should the car be incompatible materially with E10 (such as many early GDI engines, or those fitted to Historic vehicles), or the car covers a low mileage, use E5 super unleaded instead of an additive. We hope to update this advice in the future, once we receive answers that are sufficiently convincing.

About Autotechnician
Autotechnician is a magazine published nine times a year, delivering essential information to independent garage owners and technicians in the UK. Delivered both digitally and in print, autotechnician provides readers with technical, training, business advice, product and news, allowing our readers to keep up to date with information they need to run and work within a modern workshop.
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