0W-40 or 5W-40 Oil? How many quarts? 2006 Audi A8 4.2
 

Hey guys i just bought a 2006 Audi A8 4.2 with 129k miles and im wondering would 5w40 fully synthetic oil be ok to use? The previous owner used 0w40 but i got castrol edge fully synthetic oil with a audi oem oil filter. I live in Chicago and temps now are between 20s-40s. I think the car calls for 5w40 if im not mistaken? Also wondering how many quarts does it take about it 8 quarts right?