Mobil Ow 40 for the M30 motor

[ozibimmer]

Hi guys
Do you think Mobil Ow 40 oil is good for the M30 motor, I have plenty left over from my E39 540 sports last oil change. I have a E28 M535i with the M30 motor and I have Mobil one in that but it's 5w 50 weight.

[EastWind]

I just did my first oil change. They charged $31. Is that too much? Not full service, the guy said it uses a special "canister?" filter? plus 6 quarts.

How do I remove the oil service and inspection lights that are on?

okay, I found out how to reset the service and inspection light.

how hard is it to change the light bulbs in the instrument cluster? the low oil light doesn't come on, and i do really love to have that on.

[tschultz]

Some people say that 10W30 synthetic is too thin weight/ viscosity. It is my understanding that as long as you are driving in temperatures about 50 degrees and up, you could use a heavier weight oil such as 15W40. The main concern is the amount of ZDDP in the oil. Mye28.com is a good place to search, as it has been gone over numerous times.

For my M30, I drive it in the winter time and use a thin synthetic that covers the entire range of temperatures.

[ShapeShifter]

0 is too thin for the big bearing clearences of the m30.

[Bert Poliakoff]

Shell Rotella or Brad Penn Oils are high in zddp(zinc) which the M30 likes.

[euroshark]

Rotella 15w40 is a great choice. Lots of ZDDP, thick and creamy, and only around $12 a gallon at Wal Mart.

[Flash635]

You're on the Goldy so you'll never such a light oil.

You can't go past Penrite, HPR 15 for full synth or HPR 30 if you've logged a few kms.
The biggest advantage of a synth oil is that it last a lot longer than a dino, but Penrite dino will last very much longer than you're going to want it to.

I left it in an EB2 falcon for 20,000km once and it still had body and viscosity.

There's also HPR 10 Gas which is a semi synth.

[ozibimmer]

Thanks guys
I'll give the 15 a go I think, give it a engine flush and throw some good old slick 50 into the motor for good luck.

[CW6er]

Yeah, 0w is way too thin.

I think people have a misconception of what the numbers for oil mean. I suspect that some think that a 0w40 oil is a 40 weight oil that has modifiers/additives that make the oil act like a 0 weight oil at cold temps, but it is the other way around. The base oil is a 0 weight oil to which modifiers/additives are added to make the oil have the viscosity of a hot 40 weight oil when the 0 weight heats up. This is done by adding long chain molecules that are curled up when cold and then uncurl when hot to get long and increase the apparent viscosity to that of a hot 40 weight in this case. The problem is that the long chains are more likely to shear in use and lose its viscosity when hot.


Engine Oil:
I would be careful about going to a lighter (5w30/10w30)** oil in the M30.
My owners manual for my 1987 635csi has a diagram in which it shows the temperature range acceptable for various grades of oil as follows:

20w50 = aprox. 122º down to 14ºF ........ (or 50º to -10ºC)
15w50 = aprox. 104º down to -4ºF ......... (or 40º to -20ºC)
15w40 = aprox. . 86º down to -4ºF ......... (or 30º to -20ºC)
10w50 = aprox. . 68º down to -22ºF ....... (or 20º to -30ºC)
10w40 = aprox. . 50º down to -22ºF ....... (or 10º to -30ºC)
10w30 = aprox. . 40º down to -22ºF ....... (or 4º to -30ºC)
. 5w30 = aprox. . 23º down to -40ºF ....... (or -5º to -40ºC)**
. 5w20 = aprox. . 14º down to -40ºF ....... (or-10º to -40ºC)**

It also lists straight weight oils as follows:
SAE 20 from 50º down to -4ºF ....... (or 10º to -20ºC)
SAE 30 from 86º down to 32ºF ....... (or 30º to 0ºC)
SAE 40 from 122º down to 68ºF ..... (or 50º to 20ºC)

** There is a Specific Warning against using 5W20 for high speed, long distance driving even at the approved temps. which are only below 14ºF !! (Bentley Page 2-10 - Sec 3)

[RangerGress]

Be wary of Rotella. There's 3 different flavors of it, all of which has gone thru various changes to their additive packages. If you've not seen a recent oil analysis of the same flavor you're looking at, you don't know what's in it.

Re. xW50 for high temp operation. About 15yrs ago BMW came out with a tech doc for the M20B25 supporting xW40 to the same extent that they used to suggest xW50. I'm not sure why mind you. My point is that it's not precisely correct to say that xW50 is the only moderate temp oil.

Our bearing clearances are the same as yours so M20B25 info applies.

More info here: http://www.gress.org/Home/Cars/TrackTales/DIY/OilingSystem%20Improvements/Oil%20Debate/The%20Great%20Oil%20Debate.htm

Personally, I'm a big Brad Penn fan. Do a search for Navarro and LN Engineering.

[Flash635]

Be wary of Rotella. There's 3 different flavors of it, all of which has gone thru various changes to their additive packages.


And the OP is in Australia and there's no guarantee that Rotella is the same here.