Recommendation - Commuter Mazda 6 Wagon

[CptnFormat]

Hi all BITOG'ers, Coming up to my 3rd OCI on a new-to-me 2007 Mazda 6 Wagon, with the 3.0L Duratec. Car was bought used from a Mazda dealer, and had all of it's previous Oil Changes done at a Mazda Dealership in Quebec. I don't remember the exact OCI, but I believe they were longer than the recommended 8000KM/5000M listed in the owners manual. The oil _was_ changed on a regular basis. This car is a commuter car, and hauls "things" on weekends. Living just out of downtown Toronto, the car is subjected to the following during the week: 3 Days a week (Mornings)- 30KM Total 45-60 Minutes 2KM of Intown Streets 9KM of Stop and Go Highway (typically heavy traffic) 10KM of Highway Speed 9KM of Intown streets 3 Days a week (Afternoons)- 30KM total 45-60 minutes 3KM of Intown Streets Car is turned off for 5-7 minutes 6KM of Intown streets (typically heavy traffic) 6KM of Highway Speed 6KM of Stop and Go Highway (typically heavy traffic) 7KM of Highway Speed 2KM Intown Streets (Light traffic) 2 Days a week (Mornings)- 38KM total 75 - 90 Minutes 2KM of Intown Streets 9KM of Stop and Go Highway (typically heavy traffic) 10KM of Highway Speed 17KM of Intown Streets (beginning moderate and ending heavy-ish traffic) 2 Days a week (Afternoons) - 30KM Total 45 - 60 Minutes .5KM of Intown Streets 14KM Of Stop and Go Highway (Moderate to Heavy Traffic) 13KM of Highway Speed (typically light to moderate traffic) 2.5KM of Intown Streets (Light traffic) Our house does not have a garage, so the car is subjected to cold starts this time of year. Typical temperatures in the morning are -5c to -15C, until things start to warm up at the end of February. 3 days a week, the car is kept in a heated (20C) garage during the day. 2 days a week, the car is outside all day. My OCI History is: 70052 KM September 3, 2011 Royal Purple 5w20 Royal Purple Filter #20-820 78432 KM November 27, 2011 Pennzoil Platinum 5w20 Napa Gold Filter #1372 Based on the above, what should I be looking to pickup for the next OCI? A heavy 0w-20 that wont shear? Or a light 0w-30 that _will_ shear? Or am I thinking about this backwards? Edit: added engine size

 

[addyguy]

Duratecs are really easy-on-oil engines. If you are 'comfortable with the cost of using syns, just use whatever 0W-20 or 5W-20 you can get on sale at the intervals you are using - 8-10,000km.

 

[bepperb]

The most important thing on that car is to keep the PCV system clean. I wouldn't overthink the oil weight or OCI. 10,000 km sounds about right on some 0w-20 or 5w-20.