Mobil-1 15W-50 full synthetic. And your local autozone will have it in
stock. Comes with a gold cap now (used to be red) - and is called an
"extended mileage" oil. I'd suggest changing it every 6-7,000 miles
given the temps it will see. If you want to know exactly when to change
it - drain some out and have it analyzed.

Or you could use BMW Synthetic, which is a 5W-30. I suspect given your
temps that might be a bit on the thin side, but it works well as a
winter oil in the S52 engine in the eastern parts of the US.

Avoid the dealer telling you "non-synthetic" - and diesel rated oil is
generally an excellent oil with a better base oil than oils just rated
for auto use. The peak loads on bearings in a diesel engine are much
higher than auto engines, so the oil has to be very good to keep the oil
film in place protecting against metal-to-metal contact. There are some
good diesel rated oils to be found if you look at Mobil Delvac oils..
they come in both standard and synthetics.

Your S52 engine will use 7 quarts of oil. I'd suggest getting the BMW
filters - they work well (as they should) and they come with all the
seals and crush washers you need to replace them. MANN is another good
filter brand, and sometimes you can find these at autoparts stores.
Avoid Purolator - the ones I've seen in Autozone were made in India, and
I had a BAD experience with one of these where it did not meet
specifications and oil was bypassing it.

HTH

Provided the viscosity is right, I woudn't worry about "for diesel engines"
with the oil...diesels run at higher pressure and load than gasoline
engines, so I imagine the diesel is harder on the oil.  If it can stand up
to a diesel, I think it would be just fine in a gasoline engine.

The only thing I'd be concerned about is if there are any wierd additives in
it that your BMW might not get along with, but it should say if there are
any special additives on the bottle.

Tom.

Well, you certainly got a variety of answers.  What you need is another one
- especially since it will be controversial.

Anyway, the owner's manual recommendation for your car is the same as the
owner's manual recommendation for my 97 328.  I've been using Castrol
15W-40 now for 128K in my engine.  Live in Sacramento and drive all the
time (hot summers included) to Las Vegas, Phoenix and Tucson.  Engine purrs
like a little kitten.  Believe me, if oil were going to break down, mine
surely would have done it on some of the hot drives up I-5 at 115 deg in
the shade and the AC going full blast.  Here's what I've found about these
oils.

Many 15W-40 oils are rated for LIGHT  diesel (automotive) AND  heavy duty
gasoline engines.  Read the label completely - it will give all the
standards.  Be careful, there are HEAVY DUTY diesel and LIGHT duty diesel -
you need to read the label.

For example I just put a new batch of Castol GTX diesel 15W-40 in my car.
On the bottle are the following.  API service ratings CI-4, CH-4, CG-4,
CF-4, CF/SL SJ - PLUS meets Mercedes-Benz 228.1 AND ILSAC GF-3 for API
certified GASOLINE engine oils.  (Note SL, SJ ratings are gasoline engine)

Oil viscosity is important for lots of things - oil flow rate for cooling,
bearing film strength, and spray patterns.  In your engine are spray tubes
from the crank to the pistons, for example.  IT SEEMS REASONABLE to assume
that obtaining the proper spray pattern and flow rate would require the
correct viscosity - that's why I wouldn't consider any 30 weight or 50
weight oil in my car, as long as the temp is within the manual specs for
15W-40

With my  M52 engine - I follow the service interval lights. Engine runs
like a dream at 128K now.  Again, I think the secret, is using the 15W-40
dino oil recommended in the manual.
Here are few reasons

1.  These oils are diesel rated - more antiwear additives etc.
2.  My oil is still quite clean even at the 7500-8000 mile intervals that
the
service indicator comes up with.
3.  I use the Castrol, and this oil clings very well to the engine parts
even
after the car has been sitting for over a week.  Absolutely no tappet
noise,
or whatever upon startup.
4.  I think it extremely important to have the recommended viscosity (40
weight) as this affects the oil spray pattern to the pistons, across the
camshaft etc.
5.  Most important, the single step Vanos on these engines appears to be
more
reliable than the later, continuously variable, dual vanos, as it
apparently
does not need as high a pressure for operation.  Mine works seamlessly, and
I
think much of the credit goes to using the 15W-40 oil.  Again, these oils
are
diesel rated, and when you pour it in, you'll notice it is quite different
from either 10W-30, or 20W-50 oils rated for gasoline engines only.  I just

think the clearances and vanos system on these engines are designed for
this
oil.  Using it (plus premium gas) just makes the engine emit a mesmerizing
soft purr between 4 and 5K in 2nd and 3rd gear.

These 15W-40 oils just seem matched to clearances etc. in the engine.  I'm
going by the book, but I suspect there will be lots of people here saying
you'd be better with synthetic, or different weights.

I dunno - how can I trust the BMW engineers to have done such a fabulous
job in recommending the correct oil for their fabulous engine, but then
notice that everytime I climb into the car at nighttime, there is no
illumination for the stupid  red, blue air temp control knob on the dash AC
vent, so I always have to hunt for it.  Truly boggles the mind.

Frank