How to CHOOSE the right oil for you for your E39 based on what is printed on the can!
(Note: Please improve as needed so as to form a reference for others!)
Double Note: Read the spec sheet to select oil based on other characteristics (such as viscosity at other temperatures than freezing & boiling).
Choose motor oil by:
(a) quality,
(b) cold start,
(c) viscosity,
(d) type, &
(e) cost (in that order)
Never by brand!
a) QUALITY: Perhaps the most contentious of oil-selection issues shouldn't be an issue at all, because quality selection is (almost) as simple as reading the can. The can should say:
- LL-01 Approved (not "LL-01 recommended").
Note (thanks to 540M-Sport): LL-04 spec oils are NOT recommended for BMW's with gasoline engines in North America. From BimmerFile.com "What we can tell you now is that for most newer gasoline BMW models in the US the required oil must meet BMW LL-01 (approved not recommended for) specifications. There is further confusion because BMW LL-04 is recommended in gasoline and diesel engines for most other countries. In the US it will be required only for the new Advanced Diesels. The issue with the LL-04 oil in the US is that even though the sulfur content in gasoline has decreased in the US it is still not consistent. The inconsistency in levels makes the LL-04 oils not recommended in the US gasoline engines. Since the new sulfur requirements of diesel in the US require consistent levels LL-04 can be utilized in these applications."
The problem is BMW LL-01 approved oil is listed on the can of very few motor oils readily available in the USA (e.g., the only Mobil-1 that is approved is the Mobil1 SAE 0w40 variety; and you might be able to find German-made Castrol Syntec SAE 0w30 European Formula if you're resourceful, or even Pentospeed SAE 0W30, or Pennzoil Platinum European Formula Ultra SAE 5W-30, or Valvoline SynPower SAE 5W-30, etc. For more choices, please see this document listing the available LL-01/LL-04 motor oils available for sale in the USA.)
Strictly speaking, in the USA, for E39s, LL-01 is all you need to know about quality. Never assume a brand name automatically equates to the desired quality. It doesn't. Never did. Never will. Not all Mobil1 oils are LL-01 approved, for example.
- If you can't find LL-01 rated oil, then some will tell you any fully synthetic oil rated ACEA A3/B3 or better meets BMW specifications; but again, the problem is finding an oil locally available that has ACEA A3/B3 printed on the can.
- Otherwise, historically, at least in the United States, the main reliable measure of quality has been the American Petroleum Institute (API) "Service" rating (buy API SL for older BMWs or API SM or better for newer BMWs) printed on every can of oil sold in the US. This more readily available API quality designation is chronological, i.e., SA, SB, SC, SD, SE, SF, SG, SH, SI, SJ, SK, SL, & SM. Over time, this API quality designation moved higher and higher in the alphabet as more and more problems are specified and overcome by the petroleum engineers (note SA is special in that it is unspecified, and note each specification exceeds the prior specification).
- Note that anyone who says "use Castrol" or "Mobil1", without suggesting the BMW or ACEA or API quality rating, isn't providing enough information to make the right quality decision for you; brand and price and label hype are meaningless for this purpose (for example, even some BMW-branded oils don't meet BMW specifications for M cars).
b) COLD START: Depending on where you live, pick an appropriate Society of Automotive Engineers (SAE) winter (W) rating based on the range of temperatures you expect to start the car in while that oil is in the vehicle and on what is recommended in your owners manual.
It's a simple but important decision. If it's really cold where you start the BMW, use a lower SAE W rating; if it's warm, then use a higher SAE W rating (the point being to minimize the SAE spread, even for synthetics but especially for dino juice). Just remember the oil will be in the car for a few months so you have to factor in the coldest expected temperature during that time period.
Bear in mind, the SAE W rating only holds true for the first few minutes no matter what climate you live in. This rating is probably the least understood of all motor oil descriptors, but, since most wear occurs at startup, it's an important measure. Since engine oil viscosity decreases logarithmically with temperature, the SAE W rating of, say "SAE 10W", tells you that the oil "acts like" a straight SAE 10 weight oil would act at 0° Fahrenheit (°F). Remember, it is NEVER an SAE 10 weight oil! It just acts like an SAE 10 would at 0°F (i.e., before the engine is warmed up). After the engine is warm (212°F) the SAE W rating is meaningless. It is important to understand that a straight 30 weight oil acts exactly the same at engine temperatures as does a 5W30, or 10W30, or 15W30 motor oil. It is also important to understand the logarithmic decrease in viscosity still applies at all temperatures below 212°F, even though the only listed temperature is the 0°F W rating. See included charts for more details.
c) VISCOSITY: Depending on engine factors, you'll choose a warmed-up SAE oil viscosity (measured as kinematic or Saybolt) that suits you and your engine. Just pick a warmed-up viscosity that your owners manual lists as an option. That's pretty much it.
People make a much bigger issue of selecting the warmed-up viscosity than they need to. In my humble opinion, if you don't already know, before you got here, exactly which warmed-up viscosity you prefer, then simply choose the warmed-up viscosity by one of the other factors below this one in the selection criteria.
Bear in mind, it is known for dino juice the greater the spread between the SAE W rating and the SAE warmed-up rating (measured at 212°F), the greater the tendency of the dino oil to carbonize in your engine. Synthetics, I'm often told, do not have such a propensity to carbonize so the viscosity spread is much less of an issue. However, for dino juice, the simplest advice is to lean toward the closest multi-weight spread listed in your owners manual.
d) TYPE: Almost all BMW posters recommended synthetic motor oil for longevity, reduced wear and tear on gears, reduced incidence of oil oxidation, and lower sludge formation (as compared with similar quality traditional motor oils); but there are always tradeoffs, not the least of which are price considerations.
In addition, the viscosity spread, if you're going with something like a 0W40, will tend to carbonize much less with synthetic than with dino juice. However, as with many of these factors, if you change your oil religiously, in my humble opinion, it really won't make that much of a difference even theoretically; and from a practical sense, it will make even less of a difference, mostly due to the cost differential balancing out the benefits.
e) COST: Duh. As low as you can get. Buy Internet. Buy bulk. Stock ahead. If you buy good-quality (as measured by the API or BMW rating) oil, brand is nearly meaningless (see Consumer Reports' canonical diatribe on motor oil quality consistency over time).
Note (thanks to 540M-Sport): One really needs to read the specification sheets which are available online for most oils. You will find pretty significant differences between 5W-30 synthetic oils, both in viscosity at cold start up, and at operating temperatures.
More about LL-01 here ...
If you want to truly be an oil expert, read here:
http://www.bobistheoilguy.com/aehaas/
(Note: Please improve as needed so as to form a reference for others!)
Double Note: Read the spec sheet to select oil based on other characteristics (such as viscosity at other temperatures than freezing & boiling).
Choose motor oil by:
(a) quality,
(b) cold start,
(c) viscosity,
(d) type, &
(e) cost (in that order)
Never by brand!
a) QUALITY: Perhaps the most contentious of oil-selection issues shouldn't be an issue at all, because quality selection is (almost) as simple as reading the can. The can should say:
- LL-01 Approved (not "LL-01 recommended").
Note (thanks to 540M-Sport): LL-04 spec oils are NOT recommended for BMW's with gasoline engines in North America. From BimmerFile.com "What we can tell you now is that for most newer gasoline BMW models in the US the required oil must meet BMW LL-01 (approved not recommended for) specifications. There is further confusion because BMW LL-04 is recommended in gasoline and diesel engines for most other countries. In the US it will be required only for the new Advanced Diesels. The issue with the LL-04 oil in the US is that even though the sulfur content in gasoline has decreased in the US it is still not consistent. The inconsistency in levels makes the LL-04 oils not recommended in the US gasoline engines. Since the new sulfur requirements of diesel in the US require consistent levels LL-04 can be utilized in these applications."
The problem is BMW LL-01 approved oil is listed on the can of very few motor oils readily available in the USA (e.g., the only Mobil-1 that is approved is the Mobil1 SAE 0w40 variety; and you might be able to find German-made Castrol Syntec SAE 0w30 European Formula if you're resourceful, or even Pentospeed SAE 0W30, or Pennzoil Platinum European Formula Ultra SAE 5W-30, or Valvoline SynPower SAE 5W-30, etc. For more choices, please see this document listing the available LL-01/LL-04 motor oils available for sale in the USA.)
Strictly speaking, in the USA, for E39s, LL-01 is all you need to know about quality. Never assume a brand name automatically equates to the desired quality. It doesn't. Never did. Never will. Not all Mobil1 oils are LL-01 approved, for example.
- If you can't find LL-01 rated oil, then some will tell you any fully synthetic oil rated ACEA A3/B3 or better meets BMW specifications; but again, the problem is finding an oil locally available that has ACEA A3/B3 printed on the can.
- Otherwise, historically, at least in the United States, the main reliable measure of quality has been the American Petroleum Institute (API) "Service" rating (buy API SL for older BMWs or API SM or better for newer BMWs) printed on every can of oil sold in the US. This more readily available API quality designation is chronological, i.e., SA, SB, SC, SD, SE, SF, SG, SH, SI, SJ, SK, SL, & SM. Over time, this API quality designation moved higher and higher in the alphabet as more and more problems are specified and overcome by the petroleum engineers (note SA is special in that it is unspecified, and note each specification exceeds the prior specification).
- Note that anyone who says "use Castrol" or "Mobil1", without suggesting the BMW or ACEA or API quality rating, isn't providing enough information to make the right quality decision for you; brand and price and label hype are meaningless for this purpose (for example, even some BMW-branded oils don't meet BMW specifications for M cars).
b) COLD START: Depending on where you live, pick an appropriate Society of Automotive Engineers (SAE) winter (W) rating based on the range of temperatures you expect to start the car in while that oil is in the vehicle and on what is recommended in your owners manual.
It's a simple but important decision. If it's really cold where you start the BMW, use a lower SAE W rating; if it's warm, then use a higher SAE W rating (the point being to minimize the SAE spread, even for synthetics but especially for dino juice). Just remember the oil will be in the car for a few months so you have to factor in the coldest expected temperature during that time period.
Bear in mind, the SAE W rating only holds true for the first few minutes no matter what climate you live in. This rating is probably the least understood of all motor oil descriptors, but, since most wear occurs at startup, it's an important measure. Since engine oil viscosity decreases logarithmically with temperature, the SAE W rating of, say "SAE 10W", tells you that the oil "acts like" a straight SAE 10 weight oil would act at 0° Fahrenheit (°F). Remember, it is NEVER an SAE 10 weight oil! It just acts like an SAE 10 would at 0°F (i.e., before the engine is warmed up). After the engine is warm (212°F) the SAE W rating is meaningless. It is important to understand that a straight 30 weight oil acts exactly the same at engine temperatures as does a 5W30, or 10W30, or 15W30 motor oil. It is also important to understand the logarithmic decrease in viscosity still applies at all temperatures below 212°F, even though the only listed temperature is the 0°F W rating. See included charts for more details.
c) VISCOSITY: Depending on engine factors, you'll choose a warmed-up SAE oil viscosity (measured as kinematic or Saybolt) that suits you and your engine. Just pick a warmed-up viscosity that your owners manual lists as an option. That's pretty much it.
People make a much bigger issue of selecting the warmed-up viscosity than they need to. In my humble opinion, if you don't already know, before you got here, exactly which warmed-up viscosity you prefer, then simply choose the warmed-up viscosity by one of the other factors below this one in the selection criteria.
Bear in mind, it is known for dino juice the greater the spread between the SAE W rating and the SAE warmed-up rating (measured at 212°F), the greater the tendency of the dino oil to carbonize in your engine. Synthetics, I'm often told, do not have such a propensity to carbonize so the viscosity spread is much less of an issue. However, for dino juice, the simplest advice is to lean toward the closest multi-weight spread listed in your owners manual.
d) TYPE: Almost all BMW posters recommended synthetic motor oil for longevity, reduced wear and tear on gears, reduced incidence of oil oxidation, and lower sludge formation (as compared with similar quality traditional motor oils); but there are always tradeoffs, not the least of which are price considerations.
In addition, the viscosity spread, if you're going with something like a 0W40, will tend to carbonize much less with synthetic than with dino juice. However, as with many of these factors, if you change your oil religiously, in my humble opinion, it really won't make that much of a difference even theoretically; and from a practical sense, it will make even less of a difference, mostly due to the cost differential balancing out the benefits.
e) COST: Duh. As low as you can get. Buy Internet. Buy bulk. Stock ahead. If you buy good-quality (as measured by the API or BMW rating) oil, brand is nearly meaningless (see Consumer Reports' canonical diatribe on motor oil quality consistency over time).
Note (thanks to 540M-Sport): One really needs to read the specification sheets which are available online for most oils. You will find pretty significant differences between 5W-30 synthetic oils, both in viscosity at cold start up, and at operating temperatures.
More about LL-01 here ...
If you want to truly be an oil expert, read here:
http://www.bobistheoilguy.com/aehaas/