I'm doing my mother's 2007 Rav4 (4 cylinder 35,000 miles) oil change and last time I put in mobil 1 5w-20. Just a note her old oil (whatever toyota puts in it) was in terrible shape with some visible chunks. She let's it run the entire 5000 miles until the service engine light comes on solid. They also have a corolla that I put mobil 1 5w-30 EP in. Next oil change (winter) I am going to drain them both and get them on the same schedule. I want to use the same oil just for simplicity sake and I was thinking the the 5w-30 should be fine in the Rav4 even in western NY winters. Am I OK going this route?