0W-40 or 5W-30?

[cruiser132]

Hey All,

I'm getting ready for an oil change and from searching the forums, it seems that these two specific oils are suggested. I'm going to change it myself with Mobil 1 Synthetic, but the dealer and friends are all are advising different types. The X has 75k miles and I live in the Southeastern US. Since the change should last 5k miles, i.e. through winter months, ski trips, etc; does anyone here have a specific choice and reason for their pick? Thanks for the help.

[Boston X5 4.4]

Originally Posted by cruiser132

Hey All,

I'm getting ready for an oil change and from searching the forums, it seems that these two specific oils are suggested. I'm going to change it myself with Mobil 1 Synthetic, but the dealer and friends are all are advising different types. The X has 75k miles and I live in the Southeastern US. Since the change should last 5k miles, i.e. through winter months, ski trips, etc; does anyone here have a specific choice and reason for their pick? Thanks for the help.

As you have probably seen this question has been floggged to death on this and other forums ....there are almost as many opinions on this as there are on how often you should change your oil....here are some of them

(For what its worth I use 5W30 all year in Boston and feel that it gives enough of a viscosity range to cope with the summer/winter differences here)

http://www.xoutpost.com/x5-e53-forum/...highlight=0w40

http://www.xoutpost.com/x5-e53-forum/...highlight=5w30

[E61Silver]

I would use 0W30 in the cold months, since it allows easy er starting and quicker lubrication.

Another important facter is the quality of the oil. Mobil One 0W30 is high quality however American Spec Casterol is not the same as European Spec.

[vinuneuro]

Do not use Mobil 1 0W-30. M1 5W-30 is already a very thin oil relative to other 5w30 oils. 0W-30 is far too thin. Just use M1 5W-30 or any other quality synthetic and you'll be fine.

[bsprtsgrp]

Car Some Accurate Oil Information for You

--------------------------------------------------------------------------------

I have been crusing through this site and noticed there is a lot of misinformation and confusion about oil. Here are a few things you should know about oil for BMW's:

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

Cary
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but its like a different language.... so which one do you suggest if you were going to change your oil?


Unless you have an M3, in the following order:

1) Mobil 1 0w-40,
2) Mobil 1 0w-40, and
3) Mobil 1 0w-40

If you can't find the 0w-40, the Mobil 1 SUV 5w-40 is a great oil. Can't find either of these, then go to your dealer and get the BMW 5w-30.

The Mobil 1 0w-40 is a great oil, widely available (Walmart, Checker, Kragen, Autozone), and moderately priced. It is factory fill in Mercedes AMG, Porsche, and Austin Martin.

[E61Silver]

http://www.performanceoilnews.com/oi...nst_oils.shtml

This might help.

I do not under stand the reasoning behind the concept ithe oil is "too thin"?

[motordavid]

My 2Cts,
I vote for the Mobil 1 0W-40...
easy to cop and reasonably priced at any WalMart.

The "0W" will give you the cold start flowability
and the "40" top end is good for your "southeastern
US" location. The diff between 40 to 30 on mpg should
be unmeasurable in real world driving.
GL,mD

[X5 in AK]

Hey, great write up, bsprtsgrp!
Thanks for including facts and figures. Sometimes its good to keep the opinions at bay...

[bsprtsgrp]

It's not my write-up....it's one I found and pasted into this thread

[mariosp]

Excellent Explanation
Thanks