I have a 2001 Toyota Corolla. I have to refill the oil tank about once a month. No weird smells or noise or anything. The oil light just keeps coming on and the level is low. Also, my engine light also comes on regularly and I was told by my mechanic that it had something to do with the gas in my car. I need to use chevron w/ techron (thats what he told me). My car has never broken down or anything, but this is happening so often that I'm getting worried. Any explanation as to what is wrong? And how much will it cost to fix?