Hello, I am new here and looking for input on which oil to use synthetic or Con. I have heard a bit of mixed emotions regarding oil leaks developing after switching to a synthetic oil. I know you all have heard this same thing all the time on here, but maybe I can find a just answer. My truck has 130,000 miles on it (I just bought it) and am looking to switch to Mobil one. Is this a bad idea? My dad is also looking to switch, his car has 60,000 miles. Is it worth it? Should I even worry with this? What do you all think of the extended drains on the syn? like 15000 miles sounds crazy to me. I believe in staying with the man directions.