Oil Change interval and type help

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)?

Thanks

 

I use 5w20 synthetic.

This is just my opinion, but under the usage you describe I'd stick with every 5K. If it were sitting a lot year round, I'd probably go with every 6 months.

For some reason this sticks in my head: "Every 5K or 6 months, whichever comes first."

But like I said, just my opinion. Everyone has one when it comes to oil, oil filters, and change intervals. FWIW

 

5k miles or kilometers? Thanks for the input

 

I missed your location. I'm going off miles, so that would translate to every 8K kilometers or 6 months.

 

Figured you meant miles but thought it doesn't hurt to ask for clarification. Thanks again

 

Oil cap says 5w30. That'll do fine. Change it 5000 km or 6 months. If you feel you need to change it sooner. Go right ahead. You probably idle a lot to warm it up in winter. Things like this shorten the interval.