figbat
Slippery scientist
- Location
- South Oxfordshire, UK
As promised in this thread, here’s a new thread to discuss, debate and debunk some of the known ‘truths’ and myths regarding lubricating oils. This first post is likely to be quite long, so bear with me. Hopefully what will follow will be a discussion, questions, suggestions or any other commentary on the subject.
My credentials to lead this discussion? In July 1992 I graduated with a degree in chemistry and walked straight into a job with one of the world’s best-known lubricant names. Today I still work there, having spent most of that 31 years in their R&D function. I have developed and supported oils for most automotive applications as well as a significant time working with marine engines. So that’s everything from a 50cc moped to a 100,000bhp diesel engine. Right now I look after transmission oils (auto, manual, DCT, CVT, axle etc) for cars, trucks, tractors etc and also EVs.
So, where to start? Perhaps the best place is to go back to a statement I made on t’other thread, “some of what had been said up-thread is not true and some has basis in fact”, and pick out certain comments for expansion.
“two years IMO is far too long for a car not to be up on a ramp and inspected.”
OK, so the much-debated extended oil drain interval topic. First, a bit of context. Some OEMs (“original equipment manufacturer”… car maker) offer oil drain intervals up to 30,000 km or 2 years. There are a few factors behind this, but one significant one is cost of ownership. Reduced servicing cost is a selling point (to some, especially fleets). It’s actually self-harming to the OEM dealer network because this means they don’t get to see the customer as often, so fewer opportunities to get up in their face with offers, deals, new parts etc.
It is enabled by long drain oils. Oils that are capable of 30,000 km or two-year service. Note that these maxima are under perfect conditions and are usually driven by the car’s onboard computer, which monitors how the car is being used – cold starts, journey lengths, oil temperatures, throttle openings, engine load etc – and calculates the remaining oil life, telling the driver when a service is needed through a message on the dashboard.
In order to achieve this, the oils must meet long drain oil specifications. The OEMs have onerous and lengthy testing programs which an oil must complete with all results at or better than requirements. This test program includes numerous lab tests, bench tests and several engine tests and can take at least 2 years (often much longer) and significant cost to complete. Every parameter of the oil’s performance is tested: viscosity at various hot and cold temperatures, oxidation, wear, deposit control, corrosion, DPF protection, seal compatibility, often fuel economy and others. You have to pass every test and these programs are not easy to pass. What you get though, if you do pass, is an oil capable of meeting the OEM’s demands for a 30,000 km/2 year service life. I happily run cars out to their long drain intervals – I’ve done it on several cars, petrol and diesel, without issue (including cars that I actually own, not lease).
This idea that some other, lower oil change interval is more acceptable is often fixed in the past and in resistance to change. Proposing 10,000 miles or 5,000 miles usually has no basis in fact or evidence (or is anecdotal at best), just comfort with a convenient round number like those your dad and their dad used. Of course, more frequent oil changes can only be good, right? After all, the cost of an oil change is cheaper than the cost of an engine. Yes, there’s some truth in that, but it means you will be disposing of perfectly serviceable oil and thus wasting its potential and consuming more hydrocarbons. Also, every oil change is an opportunity for a cock up – a cross-threaded drain plug, a misapplication of oil, accidental ingress of a contaminant, spillage.
“[Specified brand of oil] very well respected and good value.”
I see a lot… a LOT… of recommendations for oil based on user experience that it was really good for my car, my car loved it etc (apologies to the originator of the quote above who didn’t actually say this but it is a useful segue into this topic). Many people are convinced that ‘no harm’ means ‘really good’. Almost everybody who uses an oil in a car will have no idea how well it performed, only that it survived. They will also have no idea how a different oil would have performed. Very, VERY rarely is oil performance a direct contributor to catastrophic failure. I know this because I spent some of my 31 years running our company’s investigational laboratory, which was tasked with finding the cause of failures when the finger was pointed at the oil. Every single case I saw was caused by some other factor – misapplication, contamination and over-use being the main ones. My point is that the correct oil, used correctly, should never cause you a problem regardless of source.
But – and here’s a big but – how do you know it’s the correct oil? This is where oil specifications come in. In your handbook there will be a section that deals with oil type. It will state that you must use a certain viscosity and a certain oil specification. Things quickly get very complicated at this point as you wade through an alphabet spaghetti of requirements. ACEA A3/B4, API SJ, SAE 5W-30, MB 229.51, BMW LL-04, Ford WSS-M2C-948B, VCC RBS0-2AE, STJLR.03.5122 and so on.
Industry specifications. These are OEM-agnostic specs put together to satisfy the basic requirements of most OEMs in a region. API is the American Petroleum Institute. ACEA is the Association des Constructeurs Européens d’Automobiles. Some OEMS rely only on these as enough to satisfy their needs but many don’t and create their own specifications. These build on the API or ACEA requirements but add more OEM-specific demands, such as testing in their own engines, or compatibility with their specific seal materials. Most operate an approval system – you do the testing, you submit the results to the OEM, they endorse the results and give you an approval letter. This approval is usually time-limited and is always formulation-specific – you can’t change the oil’s ingredients; if you do, the approval is lost. By the way, you can find the ACEA light duty engine oil specifications here, if you're interested.
Many oil companies jump through the hoops, do the testing, acquire the approval and put it on their labels and data sheets. Some do not. Some use judgement or ‘read across’ data from other sources to demonstrate their confidence that an oil is capable of meeting a specification, but they don’t seek formal approval. This is often shown in statements such as “meets the requirements of…” or “suitable for use in…”. Unfortunately there are not many places you can verify an approval, but there is one good one. Mercedes publish all approved oils so you can check if an oil is approved against one of their “MB” specs. If an oil says it meets an MB spec but it isn’t listed, it isn’t approved. You may then use that information to infer whatever you like about any other specs they list or claims they make.
“meets all the ACEA and API specs, and has a fistful of manufacturer approvals.”
“At the end of the day, according to industry measure, as long as the correct spec is used, any oil should be OK”
“choosing one oil over another because of some snazzy advertising claim is daft.”
Meeting a spec is like a high jump. If you clear the bar you’re through. However you get no different outcome if you just scrape over the bar compared to if you clear it by feet. This is where differentiation can come in. Some oils clear the bar by a mile and so have to find different ways to express that – you may see statements about “xx% better” or “xx% reduced wear” or whatever. The oil company is trying to tell you that the oil is more than just a list of specs and has demonstrated performance above and beyond the requirements. So whilst it is true that having an approved oil is the least you need, there may be benefits of one approved oil over another.
“There's probably only half a dozen manufacturers - it's just branded under different names to appeal to different markets. Example: there isn't a Halfords oil refinery - they purchase from Comma.”
Globally there are probably more manufacturers than you might think, but there are certainly not as many manufacturers as there are oil brands and you’re right, store brands are made elsewhere. An oil manufacturer may choose to make oil for other brands or they may not. Some oil manufacturers’ whole business model is “third party blending” (ie making oil for whoever wants it). These contracts come and go, so a store brand may be made by one company one minute and another the next.
“I seem to remember reading cheap oils will degrade quicker, particularly as heat takes its toll.”
Heat is a significant factor in oil degradation, and oil degradation is a factor in performance. It’s not really about “cheap” though, it’s about intent. Cheap oils tend not to hold many oil specs, so shouldn’t really be expected to perform as well. Some applications don’t need a lot of performance, just an oily substance and a cheap oil will do this perfectly well. Just make sure to match the requirements to the oil specifications and you’ll get the performance you need.
“The bulk of oil sold in the UK, regardless of brand or label, is actually supplied by Hunting Lubricants”
In the context of engine oils I doubt it. All the majors make their own, as well as many of the boutiques. Most of it will be imported though.
“motorcycle oil is a bit of a crock too. In terms of formulation - mainly the need not to contaminate a wet clutch with friction modifiers - it is very close to a fairly basic diesel spec oil.”
Yes, motorcycle oils need to lubricate three major things – the engine, the gearbox and the clutch. These things often have diverging needs – for example to improve power and reduce fuel consumption you want a low friction environment in the engine, but to take up drive the clutch needs high friction. Hence a bike oil needs to satisfy the engine whilst also not affecting the clutch. Car engine oils may make use of friction modifiers to eke out every last mpg and CO2 and these can interfere with clutches, so using a modern car engine oil in a bike may cause issues. However, most bikes still specify quite old-fashioned viscosities – 10W-40, 5W-40, 15W-50 etc. Oils of this viscosity are not aimed at fuel economy so will generally not be a problem to the bike. Modern car oils are 5W-20, 0W-20, 0W-16 – these viscosities do not go in bikes! Bike engines do not need the robustness of a truck engine oil, specifically the TBN (“total base number” – a measure of an oil’s ability to neutralise acids). Bike oils may also employ ingredients better suited to resisting the high shear effects of the clutch and gearbox; this high shear environment can physically break apart long chain molecules which can cause the oil to become thinner.
My credentials to lead this discussion? In July 1992 I graduated with a degree in chemistry and walked straight into a job with one of the world’s best-known lubricant names. Today I still work there, having spent most of that 31 years in their R&D function. I have developed and supported oils for most automotive applications as well as a significant time working with marine engines. So that’s everything from a 50cc moped to a 100,000bhp diesel engine. Right now I look after transmission oils (auto, manual, DCT, CVT, axle etc) for cars, trucks, tractors etc and also EVs.
So, where to start? Perhaps the best place is to go back to a statement I made on t’other thread, “some of what had been said up-thread is not true and some has basis in fact”, and pick out certain comments for expansion.
“two years IMO is far too long for a car not to be up on a ramp and inspected.”
OK, so the much-debated extended oil drain interval topic. First, a bit of context. Some OEMs (“original equipment manufacturer”… car maker) offer oil drain intervals up to 30,000 km or 2 years. There are a few factors behind this, but one significant one is cost of ownership. Reduced servicing cost is a selling point (to some, especially fleets). It’s actually self-harming to the OEM dealer network because this means they don’t get to see the customer as often, so fewer opportunities to get up in their face with offers, deals, new parts etc.
It is enabled by long drain oils. Oils that are capable of 30,000 km or two-year service. Note that these maxima are under perfect conditions and are usually driven by the car’s onboard computer, which monitors how the car is being used – cold starts, journey lengths, oil temperatures, throttle openings, engine load etc – and calculates the remaining oil life, telling the driver when a service is needed through a message on the dashboard.
In order to achieve this, the oils must meet long drain oil specifications. The OEMs have onerous and lengthy testing programs which an oil must complete with all results at or better than requirements. This test program includes numerous lab tests, bench tests and several engine tests and can take at least 2 years (often much longer) and significant cost to complete. Every parameter of the oil’s performance is tested: viscosity at various hot and cold temperatures, oxidation, wear, deposit control, corrosion, DPF protection, seal compatibility, often fuel economy and others. You have to pass every test and these programs are not easy to pass. What you get though, if you do pass, is an oil capable of meeting the OEM’s demands for a 30,000 km/2 year service life. I happily run cars out to their long drain intervals – I’ve done it on several cars, petrol and diesel, without issue (including cars that I actually own, not lease).
This idea that some other, lower oil change interval is more acceptable is often fixed in the past and in resistance to change. Proposing 10,000 miles or 5,000 miles usually has no basis in fact or evidence (or is anecdotal at best), just comfort with a convenient round number like those your dad and their dad used. Of course, more frequent oil changes can only be good, right? After all, the cost of an oil change is cheaper than the cost of an engine. Yes, there’s some truth in that, but it means you will be disposing of perfectly serviceable oil and thus wasting its potential and consuming more hydrocarbons. Also, every oil change is an opportunity for a cock up – a cross-threaded drain plug, a misapplication of oil, accidental ingress of a contaminant, spillage.
“[Specified brand of oil] very well respected and good value.”
I see a lot… a LOT… of recommendations for oil based on user experience that it was really good for my car, my car loved it etc (apologies to the originator of the quote above who didn’t actually say this but it is a useful segue into this topic). Many people are convinced that ‘no harm’ means ‘really good’. Almost everybody who uses an oil in a car will have no idea how well it performed, only that it survived. They will also have no idea how a different oil would have performed. Very, VERY rarely is oil performance a direct contributor to catastrophic failure. I know this because I spent some of my 31 years running our company’s investigational laboratory, which was tasked with finding the cause of failures when the finger was pointed at the oil. Every single case I saw was caused by some other factor – misapplication, contamination and over-use being the main ones. My point is that the correct oil, used correctly, should never cause you a problem regardless of source.
But – and here’s a big but – how do you know it’s the correct oil? This is where oil specifications come in. In your handbook there will be a section that deals with oil type. It will state that you must use a certain viscosity and a certain oil specification. Things quickly get very complicated at this point as you wade through an alphabet spaghetti of requirements. ACEA A3/B4, API SJ, SAE 5W-30, MB 229.51, BMW LL-04, Ford WSS-M2C-948B, VCC RBS0-2AE, STJLR.03.5122 and so on.
Industry specifications. These are OEM-agnostic specs put together to satisfy the basic requirements of most OEMs in a region. API is the American Petroleum Institute. ACEA is the Association des Constructeurs Européens d’Automobiles. Some OEMS rely only on these as enough to satisfy their needs but many don’t and create their own specifications. These build on the API or ACEA requirements but add more OEM-specific demands, such as testing in their own engines, or compatibility with their specific seal materials. Most operate an approval system – you do the testing, you submit the results to the OEM, they endorse the results and give you an approval letter. This approval is usually time-limited and is always formulation-specific – you can’t change the oil’s ingredients; if you do, the approval is lost. By the way, you can find the ACEA light duty engine oil specifications here, if you're interested.
Many oil companies jump through the hoops, do the testing, acquire the approval and put it on their labels and data sheets. Some do not. Some use judgement or ‘read across’ data from other sources to demonstrate their confidence that an oil is capable of meeting a specification, but they don’t seek formal approval. This is often shown in statements such as “meets the requirements of…” or “suitable for use in…”. Unfortunately there are not many places you can verify an approval, but there is one good one. Mercedes publish all approved oils so you can check if an oil is approved against one of their “MB” specs. If an oil says it meets an MB spec but it isn’t listed, it isn’t approved. You may then use that information to infer whatever you like about any other specs they list or claims they make.
“meets all the ACEA and API specs, and has a fistful of manufacturer approvals.”
“At the end of the day, according to industry measure, as long as the correct spec is used, any oil should be OK”
“choosing one oil over another because of some snazzy advertising claim is daft.”
Meeting a spec is like a high jump. If you clear the bar you’re through. However you get no different outcome if you just scrape over the bar compared to if you clear it by feet. This is where differentiation can come in. Some oils clear the bar by a mile and so have to find different ways to express that – you may see statements about “xx% better” or “xx% reduced wear” or whatever. The oil company is trying to tell you that the oil is more than just a list of specs and has demonstrated performance above and beyond the requirements. So whilst it is true that having an approved oil is the least you need, there may be benefits of one approved oil over another.
“There's probably only half a dozen manufacturers - it's just branded under different names to appeal to different markets. Example: there isn't a Halfords oil refinery - they purchase from Comma.”
Globally there are probably more manufacturers than you might think, but there are certainly not as many manufacturers as there are oil brands and you’re right, store brands are made elsewhere. An oil manufacturer may choose to make oil for other brands or they may not. Some oil manufacturers’ whole business model is “third party blending” (ie making oil for whoever wants it). These contracts come and go, so a store brand may be made by one company one minute and another the next.
“I seem to remember reading cheap oils will degrade quicker, particularly as heat takes its toll.”
Heat is a significant factor in oil degradation, and oil degradation is a factor in performance. It’s not really about “cheap” though, it’s about intent. Cheap oils tend not to hold many oil specs, so shouldn’t really be expected to perform as well. Some applications don’t need a lot of performance, just an oily substance and a cheap oil will do this perfectly well. Just make sure to match the requirements to the oil specifications and you’ll get the performance you need.
“The bulk of oil sold in the UK, regardless of brand or label, is actually supplied by Hunting Lubricants”
In the context of engine oils I doubt it. All the majors make their own, as well as many of the boutiques. Most of it will be imported though.
“motorcycle oil is a bit of a crock too. In terms of formulation - mainly the need not to contaminate a wet clutch with friction modifiers - it is very close to a fairly basic diesel spec oil.”
Yes, motorcycle oils need to lubricate three major things – the engine, the gearbox and the clutch. These things often have diverging needs – for example to improve power and reduce fuel consumption you want a low friction environment in the engine, but to take up drive the clutch needs high friction. Hence a bike oil needs to satisfy the engine whilst also not affecting the clutch. Car engine oils may make use of friction modifiers to eke out every last mpg and CO2 and these can interfere with clutches, so using a modern car engine oil in a bike may cause issues. However, most bikes still specify quite old-fashioned viscosities – 10W-40, 5W-40, 15W-50 etc. Oils of this viscosity are not aimed at fuel economy so will generally not be a problem to the bike. Modern car oils are 5W-20, 0W-20, 0W-16 – these viscosities do not go in bikes! Bike engines do not need the robustness of a truck engine oil, specifically the TBN (“total base number” – a measure of an oil’s ability to neutralise acids). Bike oils may also employ ingredients better suited to resisting the high shear effects of the clutch and gearbox; this high shear environment can physically break apart long chain molecules which can cause the oil to become thinner.
