WeHeavy

Stick to the manual's recomendations. Mobil 5w-20 and 5k is what I do.

Your wasting a lot of money on synthetic oil if your changing it less than 4k.

Oil and filters have come a long way since the early days of cars, the old change your oil every 3k is a thing of the past.

With a good filter like Wix or Napa Gold (Wix made) you should 10k on a synthetic oil change, or more.

The only real way to know for sure when to change your oil is with an oil analysis.

My wifes 2006 Cobalt tells you when to change the oil and it averages about 8k. The service manager told me the computer moniters driving habits, air temp and a host of other things to caculate when to change oil.