Is 0W-40 the best oil to use?

[Tyler]

Originally Posted by DustenT

It seems that when I use anything less than 10w30 I get oil spots, possibly from a leaking oil filter cap.

Now that you've mentioned that I've noticed some wet spots myself. I got to check my oil one of thee nights when I get home to see if it's dropped.

[tonyyy]

Originally Posted by cosmos schwarz

i must warn you, its not really possible to just try it, once mobil 1 has coated your engine parts, it aint comin' off. using a different oil brand after mobil1 may actually damage your engine, as "apparently" no other oil can lubricate these coated parts.thats what mobil say. so once youv'e used it, you have to keep using it.
it was a long time ago i heard this info, but this is what my older workmates were told when we first became a mobil1 dealer. make of it what you will. but this is what the "skeptical" people would be saying also.

Thanks for the advice Buddy !

[andy]

Does anyone have a link to Mobil 1's site or other documentation that shows using Mobil 1 forces you to always use Mobil 1? I first tried it because it's easy to get.

The nice thing about synthetic oil is that you don't have to worry about tempertature as much - since it doesn't change like dinosaur oil does, just run the right weight for your engine, and be done with it. As mentioned above, 0-40 is thicker oil than 10-30, it's just much much more consistant across a variety of temperatures.

For my M42 I ran M1 5-30 which I got analysis done every time I changed the oil. It showed this oil worked great for what I did with the engine, that is approximately 40% highway, 60% on the track. Under these conditions oil analysis proved that this oil would let that engine run safely fror about 7500 miles between changes. This doesn't necessarily mean that M1 5-30 is perfect for all conditions, just good for what I was using it for.

For my new M52 I've gone with Mobil 1's recommendation of 0-40. When I change that, I'll get it analyzed and see if it's working properly. If not, I'll change to something else.

Bottom line,

1. Go with some oil you've researched as good for the car
2. Get it Analyzed.
3. Adjust viscosity / use cycle based on the analysis.

Neither an oil company nor BMW can tell you what oil is perfect for your car based on the way you drive it. Find out for yourself.

[Icaro31]

I found this:
This is taken from another forum (e30zone)

316,316i (M10,E30) 1982-89 15w-40 / 10w-40
316i (M40, E30) 1988 - 94 15w-40 / 10w-40
316i (M40, E36) 1991-94 5w-40 / 0w-30 / 0w-40
316i (M43TU, E36) 1998 onwards 5w-40
316i/316g (M43, E36) 1993-00 5w-40
316i/Ci (M43TU, E46) 1998 onwards 5w-40, 0w-30, 0w-40
316ti (N42,E46) 2000 onwards 0w-30, 0w-40

318i (M10, E30) 1982-94 15w-40, 10w-40
318i (M40, E30) 1987-94 15w-40, 10w-40
318i/is (M42, E30) 1989-93 5w-40
318i (M40, E36) 1990-95 5w-40, 0w-30, 0w-40
318i/is (M42, E36) 1991-96 5w-40, 0w-30, 0w-40
318i (M43, E36) 5w-40, 0w-30, 0w-40
318ti (M42, E36) 1994-96 5w-40, 0w-30, 0w-40
318ti (M44, E36) 1995-00 5w-40, 0w-30, 0w-40
318i/is (M44, E36) 1996-99 5w-40, 0w-30, 0w-40
318i/Ci (M43TU, E46) 1997 onwards 5w-40, 0w-30, 0w-40
318i/Ci (N42, E46) 2001 onwards 0w-30, 0w-40
318ti (N42, E46) 2001 onwards 0w-30, 0w-40

320i (M20, E30) 1982-93 15w-40, 10w-40
320is (S14, E30) 1988-91 5w-40
320i (M50, E36) 1990-96 5w-40, 0w-30, 0w-40
320i (M52, E36) 1994-99 5w-40, 0w-30, 0w-40
320i (M54, E46) 2000-01 5w-40, 0w-30, 0w-40
320i/Ci (M52TU, E46) 1997-01 5w-40, 0w-30, 0w-40

323i (M20, E30) 1982-87 15w-40, 10w-40
323i (M52, E36) 1994-00 5w-40, 0w-30, 0w-40
323ti (M52, E36) 1994-00 5w-40, 0w-30, 0-40
323i/Ci (M52TU, E46) 1997 onwards 5w-40, 0w-30, 0w-40

325e/i (M20, E30) 1984-93 5w-40
325ix (M20, E30) 1985-93 5w-40
325i/is (M50, E36) 1990-97 5w-40, 0w-30, 0w-40
325i/Ci (M54, E46) 2000 onwards 0w-30, 0w-40
325xi (M54, E46) 2000 onwards 0w-30, 0w-40
325ti (M54, E46) 2000 onwards 0w-30, 0w-40

328i (M52, E36) 1997-01 5w-40, 0w-30, 0w-40
328i/Ci (M52TU, E46) 1998-01 5w-40, 0w-30, 0w-40

330i/Ci (M54, E46) 2000 onwards 0w-30, 0w-40
330xi (M54, E46) 2000 onwards 0w-30, 0w-40

M Coupe, M Roadster (S50, E36) 1996-00 5w-40, 0w-30, 0w-40
M Coupe, M Roadster (S52, E36) 1998-00 5w-40, 0w-30, 0w-40
M Coupe, M Roadster (S54, E36) 2000 onwards 10w-60
M3 2.3 Evo (S14, E30) 1988-91 10w-40, 5w-40
M3 3.0 Evo (S50, S50US, E36) 1992-99 5w-40, 0w-30, 0w-40
M3 3.0 Evo (S52, E36) 1996-99 5w-40, 0w-30
M3 Coupe (S54, E46) 1999 onwards 10w-60

[Icaro31]

ok people that is the last one I think that is going to answer every question that we have about this.


1) All new BMW's require synthetic. As far as weight, only certain production dates of M3's and M5's require the use of Castrol TWS 10w-60.

2) The Factory BMW Synth 5w-30 is a version of Castrol TXT Softect sold overseas. A few important things about the BMW oil a) it is a Group III hydrocracked oil which cannot be called synthetic in Europe, b) it is a heavy 30 weight (30 weight can run from 9.3-12.5cst@100c, the BMW oil is about 12.2cst), c) it is a ACEA A3 oil which means that it is approved for longer change intervals and has a HTHS (High Tempurature High Shear) measured at 150c of greater than 3.5.

3) In the US, the only Group IV PAO Synthetics that are available are 1) Mobil 1, 2) Amsoil (but not the Xl-7500), 3) Royal Purple, and 4) German Castrol 0w-30 (it has the red label and says on the back, "Made in Germany). Redline is a Group V PolyEster based oil. All other Castrol, Quaker State, Pennzoil, Valvoline "synthetics" are a Group III hydrocracked oil. It is debated how much better Group IV base oils are than group III, but generally they are considered better.

4) When looking for oil for any BMW that does not require Castrol TWS 10w-60, you want to purchase an oil that has either/both of the following ratings, a) ACEA A3, or b) BMW LL-98 or LL-01.

5) Note that Mobil 1 0w-30, 5w-30, and 10w-30 are NOT ACEA A3 or BMW LL approved oils. This is because they all are thin 30 weight oils (approximately 9.8-10 CST@ 100c) and have HTHS of approximately 3.1. Mobil 1 0w-40 and 15w-50 are A3 rated and the Ow-40 is BMW LL-01 approved. For 99% of climates and users 0w-40 or 5w-40 is the appropriate grade. There are some 0w-30 and 5w-30 oils (like the BMW 5w-30) that are forumlated on the heavier end of the 30 weight scale and are accordingly rated A3. These oils will work well also. LOOK FOR THAT ACEA A3 rating. If the oil doesn't have it, pass on it.

6) Some people seem confused about how oil thickness is measured. The first number (0W, 5w, 10w, 15w, etc) is a measurement of how thick the oil is at tempuratures of -35c- -20c (depends on the grade). The lower this first number the thinner the oil is at LOW tempuratures. The second number (30, 40, 50) refers to oil thickness at 100c (operating tempurature). 30 weight can be from 9.3-12.5 cst, 40 weight from 12.6-16.2 cst, 50 weight from 16.3-22cst (approximate). So you can have two oils, one called a 5w-30 (i.e. bmw oil) another 0w-40 (Mobil 1) that are very similar thicknesses at operating tempurature. Compare this to Mobil 1 Xw-30 which is close to a 20 weight oil at 100c. For more information here is a link with exact numbers http://www.bobistheoilguy.com/visc.html

7) BMW's recommended interval of 12,000-15,000 miles is to long. Used oil analysis has shown the BMW oil is generally depleted at 10,000 miles. Running it longer results in excess wear. It is highly recommended that you change your oil once between each BMW recommended interval (approx 7000-7500 miles). If you want to run your oil the BMW recommended interval, I would suggest that you use Mobil 1 0w-40 or Amsoil 5w-40 and change the oil filter at 7500 miles. I would encourage a full oil change at 7500 if you want your engine to last.

8) If you want to spend a few hours learning about oil, go to bobistheoilguy.com

[Mallard]

anyone here on 5w50?

[thedyingiraffe]

Originally Posted by cosmos schwarz

i must warn you, its not really possible to just try it, once mobil 1 has coated your engine parts, it aint comin' off. using a different oil brand after mobil1 may actually damage your engine, as "apparently" no other oil can lubricate these coated parts.thats what mobil say. so once youv'e used it, you have to keep using it.
it was a long time ago i heard this info, but this is what my older workmates were told when we first became a mobil1 dealer. make of it what you will. but this is what the "skeptical" people would be saying also.

I think this is the biggest bull**** I've ever read! lol

I think all of you are over reacting with oil and M42/44 engine. It's not like it cost 8k to rebuild the damn thing!

I'm using 5W30 castrol syn right now (I had mobil 1 0W40 before) because it was cheap and available.

[atlanta318ti]

Ditto. 0w40 cannot harm your engine. In theory it simply helps lubricate the engine quicker at lower temperatures. Worn oil seals tend to weep more easily after a clean fluid change. Since 0w40 is lower viscosity and may get past that worn seal a little easier, I'd be thanking the oil rather than blaming it for uncovering a potential future problem before it becomes a big one.

I Mobile 0w40 and live in Atlanta. But I normally pick it up by the case on clearance (typically in the Spring). Prior to switching I ran 5w30 Mobil Synthetic but honestly I believe my car sounds much smoother at start up with 0w40. At 155k miles and 34mpg I'll chip in the extra $1 to keep my engine clean.

[L84THSKY]

Jim @ MetricMechanics said to use 15W/50 all year round in our cars.