So I've been emailing Royal purple back and forth about a few of there oils. I wanted to get more info on there 5w40 and 0w40 for my audi that I have. The person I have been speaking with has been very helpful and when I asked him about shearing issues with RP this is what he sent me
"No Royal Purple engine oil, or any reputable engine oil (synthetic or conventional) should produce sludge in a engine unless it has been contaminated by water, coolant and/or excess fuel, or if it has been used well beyond it’s intended useful life.
All RP oils are shear stable, and shearing is not really something that is presenting an issue on any of our oils, as long as they are used within the parameters of our change interval recommendation. I have included an email response below that was sent from my supervisor to a customer regarding some of the information you will find on the internet about a oil shearing. The email response from my supervisor:
"There is a lot of misinformation on the internet spread by individuals that do not know how to properly interpret used analysis reports, as well as by Amsoil and their “independent distributors”. In appropriate automotive service I would not expect to see meaningful shearing of the VI of ANY reputable oil, whether it is Amsoil, Royal Purple, Castrol, Pennzoil, Mobil 1, or any other quality oil. Reputable engine oils that are commonly available in the US, Canada, and Europe really don’t have this problem. There are two primary sources for information that claim a particular oil “sheared”: 1. On a forum to which someone has posted a UOA (used oil analysis) report; and 2. An Amsoil affiliated website.
UOA Reports:
Most of the time, when an internet forum thread contains a used oil analysis report that shows a particular oil “sheared”, the root cause is usually dilution by fuel and/or coolant. These UOA reports typically have a column or row that specifically lists fuel and glycol content, so a commenter may point out that the report shows little to no fuel or coolant. However, the tests used to determine fuel and glycol are notoriously inaccurate with some lubricant chemistries. Determining actual used oil condition is a trending process (not just one sample) and several analysis methods may need to be employed. The UOA reports posted are almost always from the same lab, and include only elemental spectrometry, viscosity (sometimes at only one temperature) and maybe flash point. Dilution of the oil can be determined by a drop in viscosity with a corresponding drop in elemental content. However, without a new/unused baseline to actually compare the used sample to, the real reduction in viscosity and elemental content cannot be determined. Please note the “Universal Averages” are universally incorrect.
The individual that posts the UOA report typically deduces “shearing” based only on a reduction in viscosity. This is to be expected, though, because the defined ranges for SAE viscosity grades are easily available (search for SAE J300). Conversely, the elemental content for a particular oil formulation is not widely available (because manufacturers don’t typically list formulation information) and actual numbers for a particular bottle of oil will vary slightly from the elemental content of a different bottle of the same oil that was made in a different batch. Automotive lubricants are almost always made in batch production of several thousands of gallons at a time, and slight batch to batch variations in finished product are a fact of lubricant production. Another tool that labs use in oil analysis is an infrared scan (FTIR is most common). The IR scan provides qualitative information on the molecular compounds that are in the sample, vs. the elemental analysis that only shows elements. Pro Tip: Lubricants are not manufactured with elements, rather molecular compounds, so an elemental oil analysis report provides very little useful detail on the sample oil’s formulation.
I’m getting off-track a bit, but the take away from all of the above is that the UOAs often posted online tell an incomplete story. Also, the person on the forum interpreting the report often doesn’t have a deep enough understanding to provide an accurate “diagnosis”.
Amsoil White Papers and “Testing”:
In a nutshell, most of the information provided in these documents is meaningless (at best) and misleading/inaccurate (at worst). Amsoil alters test parameters (temperatures, loads, speeds, etc.) in the some of the “standardized” ASTM tests they purport to use, and they rarely publish the actual test data and how many times they ran a particular test to achieve the results. Also, most of the ASTM tests they run against competitor oils are not meant to be comparative between candidate oils. These tests are meant to be PASS/FAIL against a reference oil only because the tests have repeatability and reproducibility errors as high as 20%. The bar graphs most commonly published by Amsoil are worthless. Furthermore, we have caught them spreading absolute lies about competitors. For example, Amsoil claimed that we (Royal Purple) use molybdenum disulfide (an insoluble lubricity enhancer) in some of our engine oils, and that Cummins recommended against using RP engines oils. The problem with these claims is that we don’t use ANY insoluble additive in ANY of our lubricants AND we have approval letters from Cummins for our diesel engine oils. Amsoil makes very good lubricants, but their marketing has historically been inaccurate and misleading.
To summarize, Royal Purple oils do not shear in use in an appropriate application and within our guidelines. Furthermore, I have never seen a report of a Royal Purple engine oil that actually did shear; contamination is almost always the root cause of a significant change in viscosity and content. I would expect similarly good shear stability from Amsoil and other high-quality engine oils available. Though shearing an engine oil is certainly possible, it is extremely rare for a reputable oil to become damaged within its recommended usage."
"No Royal Purple engine oil, or any reputable engine oil (synthetic or conventional) should produce sludge in a engine unless it has been contaminated by water, coolant and/or excess fuel, or if it has been used well beyond it’s intended useful life.
All RP oils are shear stable, and shearing is not really something that is presenting an issue on any of our oils, as long as they are used within the parameters of our change interval recommendation. I have included an email response below that was sent from my supervisor to a customer regarding some of the information you will find on the internet about a oil shearing. The email response from my supervisor:
"There is a lot of misinformation on the internet spread by individuals that do not know how to properly interpret used analysis reports, as well as by Amsoil and their “independent distributors”. In appropriate automotive service I would not expect to see meaningful shearing of the VI of ANY reputable oil, whether it is Amsoil, Royal Purple, Castrol, Pennzoil, Mobil 1, or any other quality oil. Reputable engine oils that are commonly available in the US, Canada, and Europe really don’t have this problem. There are two primary sources for information that claim a particular oil “sheared”: 1. On a forum to which someone has posted a UOA (used oil analysis) report; and 2. An Amsoil affiliated website.
UOA Reports:
Most of the time, when an internet forum thread contains a used oil analysis report that shows a particular oil “sheared”, the root cause is usually dilution by fuel and/or coolant. These UOA reports typically have a column or row that specifically lists fuel and glycol content, so a commenter may point out that the report shows little to no fuel or coolant. However, the tests used to determine fuel and glycol are notoriously inaccurate with some lubricant chemistries. Determining actual used oil condition is a trending process (not just one sample) and several analysis methods may need to be employed. The UOA reports posted are almost always from the same lab, and include only elemental spectrometry, viscosity (sometimes at only one temperature) and maybe flash point. Dilution of the oil can be determined by a drop in viscosity with a corresponding drop in elemental content. However, without a new/unused baseline to actually compare the used sample to, the real reduction in viscosity and elemental content cannot be determined. Please note the “Universal Averages” are universally incorrect.
The individual that posts the UOA report typically deduces “shearing” based only on a reduction in viscosity. This is to be expected, though, because the defined ranges for SAE viscosity grades are easily available (search for SAE J300). Conversely, the elemental content for a particular oil formulation is not widely available (because manufacturers don’t typically list formulation information) and actual numbers for a particular bottle of oil will vary slightly from the elemental content of a different bottle of the same oil that was made in a different batch. Automotive lubricants are almost always made in batch production of several thousands of gallons at a time, and slight batch to batch variations in finished product are a fact of lubricant production. Another tool that labs use in oil analysis is an infrared scan (FTIR is most common). The IR scan provides qualitative information on the molecular compounds that are in the sample, vs. the elemental analysis that only shows elements. Pro Tip: Lubricants are not manufactured with elements, rather molecular compounds, so an elemental oil analysis report provides very little useful detail on the sample oil’s formulation.
I’m getting off-track a bit, but the take away from all of the above is that the UOAs often posted online tell an incomplete story. Also, the person on the forum interpreting the report often doesn’t have a deep enough understanding to provide an accurate “diagnosis”.
Amsoil White Papers and “Testing”:
In a nutshell, most of the information provided in these documents is meaningless (at best) and misleading/inaccurate (at worst). Amsoil alters test parameters (temperatures, loads, speeds, etc.) in the some of the “standardized” ASTM tests they purport to use, and they rarely publish the actual test data and how many times they ran a particular test to achieve the results. Also, most of the ASTM tests they run against competitor oils are not meant to be comparative between candidate oils. These tests are meant to be PASS/FAIL against a reference oil only because the tests have repeatability and reproducibility errors as high as 20%. The bar graphs most commonly published by Amsoil are worthless. Furthermore, we have caught them spreading absolute lies about competitors. For example, Amsoil claimed that we (Royal Purple) use molybdenum disulfide (an insoluble lubricity enhancer) in some of our engine oils, and that Cummins recommended against using RP engines oils. The problem with these claims is that we don’t use ANY insoluble additive in ANY of our lubricants AND we have approval letters from Cummins for our diesel engine oils. Amsoil makes very good lubricants, but their marketing has historically been inaccurate and misleading.
To summarize, Royal Purple oils do not shear in use in an appropriate application and within our guidelines. Furthermore, I have never seen a report of a Royal Purple engine oil that actually did shear; contamination is almost always the root cause of a significant change in viscosity and content. I would expect similarly good shear stability from Amsoil and other high-quality engine oils available. Though shearing an engine oil is certainly possible, it is extremely rare for a reputable oil to become damaged within its recommended usage."
