My 2007 Sierra has always had this problem with burning synthetic oil. The truck almost has 200K on it. When I bought it in 2009, it had just over 30K and I had this problem back then. It doesn't do this with conventional oil, just synthetic. I regularly change my oil and ensure that I'm using the correct amount and viscosity. Thoughts?
So you are saying it does not burn oil at all if you use conventional oil. Correct? It is a weird situation but if this is the case, just use conventional oil.
It's weird, I know. I've been using conventional for the most part, but I thought I would try synthetic again just to see if the issue happens again and it did. I don't have a problem with conventional.
Did you use the same viscosity for both oils?
Yes, 5W-30.
Apparently, your car does not like synthetic oil. Still have no explanation for that, but the good thing is that you can switch to conventional oil and solves the issue.