Ok First let me state that I did a search but couldn't find any info that matched my situation.
In the non winter months I use my truck once a week if that (I do a lot of biking and running). My truck is a 2007 and I just hit 50,000 KM's.
In the summer we see +40 degrees C and the Winter we can see -40 degrees C.
I use synthetic 5w30 in my truck. How often should I be changing it?
Should I go by months or mileage?
I found an old work report from the dealership (November report) and noticed that they were putting 5w20 in my truck. Should I be using 5w30 (which is written on the oil filler cap) or 5w20 (which is recommended in the manual)?