Is Mobil 1 0w40 wrong oil for older BMWs?

[Russell]

I just had a very reputable BMW mechanic advise me that Mobil 1 0w40 is the wrong oil for older BMWs with over 50,000 miles. He suggests 15w50 here in Kentucky.

I see opinions all over the place on this issue.

[Hector]

and one thing I don't hear mentioned is the temperature range of "operation" of each oil. The Bently manual has a chart with various oil weights and associated temperatures but here that seems to go out the window. Actually, that chart is confusing to me. Does it mean that for a particular oil, the oil will breakdown if outside the specified temperature range, or is it the ambient temperature for which the car is driven in? What's the verdict?

[Bill R.]

you can do a straight comparison of the three most common mobil one oils and make your own judgement. 0w40 is clearly superior imho. Even the flash point is higher than 15w50 which indicates that consumption would be lower.
Here's ow40

Heres 15w50

Here's 5w30

I just had a very reputable BMW mechanic advise me that Mobil 1 0w40 is the wrong oil for older BMWs with over 50,000 miles. He suggests 15w50 here in Kentucky.

I see opinions all over the place on this issue.

[Hector]

Bill, what is flash point?

[Bill R.]

Flash point is the temperature at which oil give off vapors that can
be ignited by a flame held over the oil. The lower the flash point the greater the tendency to suffer vaporization loss... Ie. Oil consumption..
4ooF is the minimum recomended to prevent excess oil usage. Flash point can be an indicator of the quality of the base stocks used ...

Bill, what is flash point?

[shragon]

don't use the charts found in the bentley or the manual. those are charts for DINO OIL and do not apply to synthetic.

i currently use mobil-1 5w30 and thinking of switching to 0w40.

[632 Regal]

Dammit...now that I just changed my oil. well I'll have enough time to get some 0w-40 for the next change.

[Russell]

0w40 it is. However, he is still reputable. He has worked on my last three BMWs. Bit cranky and/or opinionated at times, but very good to work with.

Not sure why he thought 15w50 is best. Need to ask.

you can do a straight comparison of the three most common mobil one oils and make your own judgement. 0w40 is clearly superior imho. Even the flash point is higher than 15w50 which indicates that consumption would be lower.
Here's ow40

Heres 15w50

Here's 5w30

[Bill R.]

back, but oils seem to be one of the things that actually get better

0w40 it is. However, he is still reputable. He has worked on my last three BMWs. Bit cranky and/or opinionated at times, but very good to work with.

Not sure why he thought 15w50 is best. Need to ask.

[BigD]

Bill, what's your opinion of that 10w60 Castrol/Agip stuff (TWS or Forumula RS or something)? It's expensive as hell but I hear it's the best.

back, but oils seem to be one of the things that actually get better