The Ultimate Oil Thread.

[hamoodi_7]

Now I have been reading a lot of forums regarding oils and what brand to use. There are many opinions and speculations going on in the these forums that still left me undecided. I have been using the OEM 5W-40 ever since I got the car but the previous owner has been using Mobil1 0W-40. Also, the oil to be used is heavily dependent on the climate. So my question is: Which is the best oil to use in the UAE climate for non-M's?
(M-owners have it easy, just use castrol edge sport 10W-60 and you're all good :P)

[Ayham]

Before we see the replies here based on individual experiences and thoughts, I figured it's better we lay down some scientific facts first. These should be the basis for your comparos.


Q: 10W60. What does it mean?

A: 10 is the oil grade at 0C (or cold temperatures). 60 is the oil grade at 100C (Operating temperature).


Q: Which is thicker and which is thinner?

A: The lower oil grade is thinner than the higher one. That is, a lower oil grade is less resistant to flow compared to a higher grade oil. That is, it is more viscous compared to a higher grade oil. Example? 20W50 is less viscous/flows harder than 10W60 at cold temperatures (20 > 10), and vice versa at 100C (50 < 60).


Q: When to use a certain grade of oil?

A: In cold weathers, lower grade oils are used to facilitate cold start lubrication. As the engine temperature builds up, the oil becomes thicker, courtesy of Viscosity Improvers (IV) added to the oil that would allow the oil to be of the 10 oil grade at cold start and thicken to no more than the indicated 60 oil grade at 100C.


Hopefully this will keep your posts in check....Fire away.

[SewerSideUp]

Correct me if I'm wrong, but oils thin out as they get hotter which eventually leads to a loss of oil pressure in the engine when it gets too hot. Mineral oils ofcourse, not synthetic.

[Ayham]

Wirelessly posted (BlackBerry8520/4.6.1.272 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/212)

Synthetic oils have polymers engineered to "clog" as the temperature increases. This provides the enough protection needed for the engine at higher operating temps.

[Hasan Shaikh]

I would suggest a 10W-40 for non ///M cars.

If you feel that the engine is running too light towards the end of the oil life you might want to go with 10W-50.

[ahmad.alkhalil]

thank you Ayham for the clarification

[hamoodi_7]

Hmmm... Well, 10w-40 is under what brand name?
Also, I read many threads of people sticking to a brand called royal purple which seems to be unavailable here. Also a long life list of oils are recommend by BMW in 2001. Those include mobile1 0w-40 and other castrol oil. People have said that mobil1 can produce something called vanos rattle or something (not sure what that meant). Comments?? :D

[Ayham]

VANOS rattle is caused by weary O-rings and seals...

For BMW I'd stick with Castrol or Mobil..Some race teams would go for Valvoline and Liqui Moly, but racing conditions are nothing to compare daily driving conditions to.

[Hasan Shaikh]

+1 to Ayham.

I would also prefer Castrol. Almost all grades should be avaiable with them.

[Maxi]

What I know that it should be synth. oil first, then look for the grade.

But what is better grade for hot days like these days?

[SSense]

What I know that it should be synth. oil first, then look for the grade.

But what is better grade for hot days like these days?

There are oil grades such as 0W, 5W, 10W, 15W, 20W, 25W, etc.. Go for anything higher than 5W.. 5W is suitable for cold places, here mostly we use 10W..

[Hasan Shaikh]

There are oil grades such as 0W, 5W, 10W, 15W, 20W, 25W, etc.. Go for anything higher than 5W.. 5W is suitable for cold places, here mostly we use 10W..

If I am not mitsaken, thats the cold temp rating Ali is referring to.

For hot climates 10W-40 or 10W-50 is good.

[SSense]

If I am not mitsaken, thats the cold temp rating Ali is referring to.

For hot climates 10W-40 or 10W-50 is good.

Thats what I said, go for anything higher than 5W..

There are oil grades such as 0W, 5W, 10W, 15W, 20W, 25W, etc.. Go for anything higher than 5W.. 5W is suitable for cold places, here mostly we use 10W..

[Hasan Shaikh]

Ok!

My mistake sorry. :runaway:

:sorry: