What oil....?

[Jake Casson]

For a E34 535is would you say is best, 10w-40?

[SRR2]

That's like asking what religion you think is best.

[joshua43214]

The owners manual (not shop manual) is your best friend here.

[SRR2]

Unfortunately for cars that are 17 years old, it's not, unless you wanted to know what oil to use 17 years ago. Times change, so does oil.

IMO, the BMW requirements for current production should be taken as good advice for older cars too. And those are in a nutshell, 5W-30 or 0W-40 quality synthetic oil, API-SM. If you follow the owner's manual you'd be looking all over for API-SF mineral oil.

I suspect you'd find that the majority of people here use something like Mobil1 in grades of 5W-30, 0W-40, or 10W-30, in that order of popularity. But that's just a guess.

If you live in the States, Mobil1 5W-30 is a pretty good deal at Wallyworld these days. A five quart jug can be had for under $21. That's hard to beat.

Except for the Porsche, which requires 0W-40, I use 5W-30 for all cars in the fleet. They seem happy with it, and I'm satisfied with the results at 7K to 8K mile change intervals.

[DueyT]

FWIW, I use Mobil 1 0W40...very happy with how the motor looks inside!

Cheers,
Duey

[BASEBALL248]

Mobil 1 Syn 5w-30 in the BMW (year round).
Mob 1 Syn 15w-50 in the Twin Turbo (summers only).

[632 Regal]

M1 0w40

[Jake Casson]

Here in the UK I would use a Comma oil, still wondering what one...?

5W-30 or 0W-40 do you think, does climate make a difference?

[632 Regal]

is that synthetic oil?

Here in the UK I would use a Comma oil, still wondering what one...?

5W-30 or 0W-40 do you think, does climate make a difference?

[SRR2]

I think climatic effect on oil selection is grossly overstated in water cooled engines. After all, the operating temperature is maintained by the thermostat regardless of ambient temperature. Air cooled engines are a different ball of wax of course. IMO the only thing that you need to worry about in choosing oil viscosity range is 'how cold does it get in winter?' Since you're in the UK, the answer is 'not very' (we on this side of the Pond accept your gratitude for the Gulfstream, BTW) , so a 5W-30 ought to work fine for you. I use that weight and it's been fine in winter weather down to -15F which it hits here every couple of years. The only place I use the 0W-40 is where the manufacturer explicitly dictates.

'Comma' oil. You guys have such funny names for things. 8-)