Since I've found scattered info about this I'd thought I'd stick an information post up.

Straight from a mechanics mouth at Audi in Miramar, San Diego, this is what he suggested..,

Castrol or Mobil 1
full synthetic 5w/40

He doubly cautioned about going back to traditional oil on accident after going synth. Just some info I'd thought I'd share.

Don't let yer meat loaf!
-M

 

mobil 1 5w-40 and 0w-40 are both VAG apporved, although i haven't looked if castrol was, although the M 1 website recommends 0w-40 for A6's but it doesn't matter. i use M 1 but i've heard some really good things about elf excellium, little more expensive than M 1 but it's supposed to be one of the best and it is also VAG approved.

 

Hmmm... While we're discussing this, how about Mobile 1 5W-30? Just had that put in today because it was the closest thing the dealer had (and I've got three coupons for free oil changes). Not on the official recommended list, but any thoughts to reassure me?

 

I was asking a European mechanic that was referred to me by a friend today about what oil to use in my 2002 A6 2.7T - he said Mobil 1 synthetic 15-50. I'm getting ready to research -

 

15-50 seems REALLY thick. ALL of the articles I've said advised to keep it looser than that. Are you in a cold climate? The recommended list by Audi contains over 200 oils and with only 19 exceptions (each 5W-30), all of them are 0W-40.

 

To clarify... a winter weight of 15 in a cold climate would really starve the turbos of needed oil until the car is warmed up quite a bit. A lower winter grade will flow more readily when cold. The 50 number will give you greater resistance to breakdown, but if you go synthetic, you're already getting a lot of protection in that regard so 50 seems overkill.

 

So.. In a milder climate (san diego)... a lower 'winter' (w) is sufficient?

 

I'm not an oil expert, but here's my understanding...

The first number represents how eaily the oil flows when it's cold. The lower the number, the easier it flows. So, in really cold climates, you want to go with a 0 weight. In warmer climates, a higher number is OK -- maybe a 5. The need to go with a 10 -- which offers higher resistance to viscosity breakdown -- is reduced when you go with a synthetic.

The second number refers to the tendency to resist viscosity breakdown at high temperatures. Again, a synthetic will help you in this regard. If you never drive hard and avoid desserts, 30 would be fine. If you drive pretty hard or are often in hot climates, you'll probably want to run 40. 50 and up tends to be for really harsh environments like the track. San Diego might just be warm enough to merit that kind of weight, but I wouldn't tend to think so. One of the prices you'll pay with these higher grade (i.e., thicker) oils is lower gas mileage. This last fact (and the closer tolerances used to manufacture modern engines) is the driving force behind the move toward lighter oils.

Most of the oils Audi recommends are 0W-40. Great low temp flow in the cold (to get those turbos the oil they need early) and good resistance to high temp brakedown (those same puppies can run pretty hot). They consider 5W-30 an acceptable alternative. Because the second number is lower, you might want to change it more often.

I've actually done a bit of research on this today and there are a LOT of opinons out there. Plenty will contradict mine. FWIW, I've tried to put together the best synopsis I could.

 

That is some great info S.Bend. Thanks for the follow-up.

I'm guessing a lot of us scratch our heads in the oil aisle... which makes me less like an idiot

 

M 1 5w-30 is not synthetic is it?? if it's not synthetic do not use it. That would be alright for a 2.8 although i use synthetic in mine, but because you have a 2.7t you need synthetic for the turbos. non synthetic will ruin your turbos.