BMW 3-Series (E90 E92) Forum - View Single Post - Oil change -- what oil to use?

Surly73 · 05-11-2012, 07:41 AM

Hi all:

I'm new to the E90 platform, but not to BMWs and I know lots about oil.

The N52 has even more oil-operated doohickeys than the older cars, but a general rule of thumb to remember is that BMW LL-01 is only required if you plan on going to full service interval and/or you are under some sort of warranty and don't want to take chances with warranty coverage.

If you plan to change more often (2-3x the factory service interval) you don't have to shop for LL-01 specifically, but I would recommend shopping for ACEA A3 if you are looking at any 30 weight oils. ACEA A3 is the basis for LL-01 and mandates some minimum specifications for HTHS specifications. HTHS pertains to thickness when subjected to shearing forces. For the record, a BMW driven by an enthusiast results in lots of shearing.

ACEA A3 rated oils have a minimum starting HTHS rating and are supposed to have a minimum level of shear resistance over the life of the oil. HTHS is not the same as viscosity, although an oil with higher HTHS at the same viscosity is a "better engineered" oil.

In general, high performance European engines expect certain shear behaviour.

So, if you're looking at 0W30, 5W30, 10W30 or 0W40 look for ACEA A3. If you're looking at 5W40, 10W40, 15W40 and up you're probably OK since these thicker oils naturally have higher HTHS values. You will find that relatively few 30 weight oils earn ACEA A3. This is because they need to be extremely tough while still being "thin". I believe that German Castrol 0W30 is the only 0W30 on the market to earn ACEA A3. It's no coincidence that it also has LL-01.

BMW's 5W30 is not the same as Syntec 5W30. BMW's blend has higher HTHS and is at the thick end of being labelled a 30 ("30" is actually a wide range of viscosity). Just because the owner's manual says "5W30" doesn't mean you should put any 5W30 in there. Mobil1 5w30 is dramatically thinner than BMW's, and thinner at operating temperature than Castrol 0W30, for instance.

I performed lab analysis on the used oil from my M52 on a regular basis (every other OCI or so) to confirm that I was seeing good engine wear, no contamination, and that the oil was not heavily sheared, stayed in grade and had enough acid fighting additives to remain viable at my oil change interval.

Lab analysis is really the only way to tune your oil change interval to YOUR engine, YOUR driving, YOUR climate and YOUR choice in oil.

I don't have enough experience with the N52 yet to see how sensitive they are to specific viscosity in the field. "Protection" and "operation" are potentially two completely separate factors. You can have complete protection from engine wear but if your VANOS or Valvetronic doesn't work properly then who cares?

05-11-2012, 07:41 AM	#63
Surly73 Lieutenant Colonel 535 Rep 1,873 Posts Drives: '11 535xi 8AT KWv3 MPE MHD xHP Join Date: May 2012 Location: Oakville, Ontario iTrader: (1)	Hi all: I'm new to the E90 platform, but not to BMWs and I know lots about oil. The N52 has even more oil-operated doohickeys than the older cars, but a general rule of thumb to remember is that BMW LL-01 is only required if you plan on going to full service interval and/or you are under some sort of warranty and don't want to take chances with warranty coverage. If you plan to change more often (2-3x the factory service interval) you don't have to shop for LL-01 specifically, but I would recommend shopping for ACEA A3 if you are looking at any 30 weight oils. ACEA A3 is the basis for LL-01 and mandates some minimum specifications for HTHS specifications. HTHS pertains to thickness when subjected to shearing forces. For the record, a BMW driven by an enthusiast results in lots of shearing. ACEA A3 rated oils have a minimum starting HTHS rating and are supposed to have a minimum level of shear resistance over the life of the oil. HTHS is not the same as viscosity, although an oil with higher HTHS at the same viscosity is a "better engineered" oil. In general, high performance European engines expect certain shear behaviour. So, if you're looking at 0W30, 5W30, 10W30 or 0W40 look for ACEA A3. If you're looking at 5W40, 10W40, 15W40 and up you're probably OK since these thicker oils naturally have higher HTHS values. You will find that relatively few 30 weight oils earn ACEA A3. This is because they need to be extremely tough while still being "thin". I believe that German Castrol 0W30 is the only 0W30 on the market to earn ACEA A3. It's no coincidence that it also has LL-01. BMW's 5W30 is not the same as Syntec 5W30. BMW's blend has higher HTHS and is at the thick end of being labelled a 30 ("30" is actually a wide range of viscosity). Just because the owner's manual says "5W30" doesn't mean you should put any 5W30 in there. Mobil1 5w30 is dramatically thinner than BMW's, and thinner at operating temperature than Castrol 0W30, for instance. I performed lab analysis on the used oil from my M52 on a regular basis (every other OCI or so) to confirm that I was seeing good engine wear, no contamination, and that the oil was not heavily sheared, stayed in grade and had enough acid fighting additives to remain viable at my oil change interval. Lab analysis is really the only way to tune your oil change interval to YOUR engine, YOUR driving, YOUR climate and YOUR choice in oil. I don't have enough experience with the N52 yet to see how sensitive they are to specific viscosity in the field. "Protection" and "operation" are potentially two completely separate factors. You can have complete protection from engine wear but if your VANOS or Valvetronic doesn't work properly then who cares?
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