So I've read a lot today and that caused me to post a new thread. I am wondering if I put synthetic oil say 5w40 or even 10w40 would it slow down or change oil consumption? Right now with conventional it uses a quart every 1400 miles its a saturn sl2. What do you oil gurus recommend what I've read tells me to use synthetic but my old ways say its not wise. What do you guys think? Thanks