Oil weight

[Island530i]

I'm trying to get an answer to my question on oil weight. I'm not sure what weight and brand or type is recommended for a 95 530i with 160,000 miles in a pretty broad temperature range summer=100, winter=20. Any help would be greatly appreciated.

[Russell]

5w40 synthetic would work fine. Pick your brand

[tim]

I think your spec is for 15w50.

Which most people around here think is too thick for year round use. It's ok for the summer, but as russell said, 5w40, or even 0w40 (mobil one or castrol syn) would be fine. IMHO, don't go for the 5w30. You want the second number to be 40 or better and at least a 35 pt spread to the cold wt number.

[Tiger]

I agree.. 5W or 0W40 SYNTHETIC is all you need regardless of temp. Use it for 10,000 miles at a time.

[632 Regal]

Mobil 1 0w-40 will work very well for you.

[t_marat]

In oil markings, for example 0W-40; OW stands for viscosity (weight). What for is the 40?

[rob101]

"the winter grades of 5W, 10W and 20W are determined by the oils' viscosity at 0° Fahrenheit (-18°C), while grades 20,30, 40 and 50 are determined by its viscosity at 212° Fahrenheit (100°C)"

however the W rating (W for Winter) doesn't seem to be as simple as viscosity as OW is not a viscosity rating as no oil can have a viscosity of zero it relates to something called a pour point.:D

http://www.chris-longhurst.com/carbibles/engineoil_bible.html

http://www.sae.org/news/rightoil.htm
probably believe what you see in the SAE article over the oil "Bible" and its greasy prophets, as SAE created the naming system/standard (J300).

[Island530i]

Thanks for the help. Much appreciated

[Gayle]

If you need more food for thought on the topic of oil, try this site:

Bob is the oil guy (http://www.bobistheoilguy.com)

"Unlike most private motor oil web sites, Bob Is The Oil Guy is not about selling you something. It's about educating you so you can make informed decisions about the life blood of your engine: motor oil."

[Russell]

That site is a bit addictive. You find yourself wanting to know more about oil than a oil engineer should know. Then there is the worry/concern/issue about used oil analysis. Not if, but how often! Don't forget should you use oil and fuel additives?? Trying to break myself of visiting and posting there.