i have been using 0w-40 and upon further analysis i have read that 0w-40 might not be so wise to use in summer (from former threads)

some say to use 5w-30 5w-40 in the summer and some say to use 10w-30 which i think would be too thick for my 2.7.

what i dont understand is since 0w-40 and 10w-40 are 40 weights they would provide the same protection in the heat right? i would think the 0w-40 is best to use in summer because i get 40 protection and 0 at cold starts? unless i have misread/misunderstood how oils are weighed.

the temps in my state are in 100F in summer if not hotter and gets to be 60F in winter.
there may be some unusual days where the temp reaches 30 but mostly its around 60 in winter.

i have a 02 2.7t w/tip

so what do yall say? should i stick to m1-0w-40 in the summer or switch to valvoline 5w-40?

 

stick to a 40 weight SAE oil. The 40 is the SAE viscosity rating at engine operating temperature. In 0W-X and 5W=X, the numbers before the W are the viscosity ratings of the oil at low temperatures. A 0W will be more "fluid" at start-up and "flow" more quickly through the motor. At operating temperature both oils will be operating as if they had a 40 weight rating.

You should be just fine running 5W-40 as opposed to 0W-40. just stick to regular changes and make sure you are using "fully synthetic" oil

 

If the 0w-40 comes on sale ill use it in the summer. but for now after doing research it seems that lots of people use Shell t6 5w-40.

only thing that concerns me is it is diesel oil and the back of the bottle says to compare to 15w-40 which i think is really thick for cold starts.

also i have 3 quarts of 0w-40 left would it be OK to use that 3 quarts and mix the remainder of oil with shell t6?

 

I use T6 in my car and have not had any issues. The jury is still out on whether I'm an idiot for doing so, or not.

As far as mixing oil goes, the general consensus is that oil is oil and you can't/wont hurt anything by mixing them. That said, most seem to believe that it is always preferable to use the same oil, only mix in "emergencies" to hold you until you can do an oil change.

as someone posted in another thread about oil, "it is worth it to me to spend a couple of extra bucks for an oil change than to risk damaging my engine".

-not an expert

 

The Mobil-1 0W-40 is in Audi's approved oil list ... you are safe.
If you want to change oil brand, refer the list again.

http://microsites.audiusa.com/ngw/09..._1997-2012.pdf