Before I knew anything about cars and started coming to BITOG for the first time ever: I believed that different oils caused different RPMs and had a huge impact on engine temperature. I also made every excuse in the world to change my oil out every chance I could based on little sounds, noises, and feelings while driving. (The engine didn't start as easily - the oil must be sludged!!!)
Now, having spent time on BITOG, reading some technical data... I've become a lot wiser and a whole lot less worried about my car. Oil is Oil is Oil. They all perform about the same - the differences are close to splitting hairs... Long as you change your oil regularly your engine will outlast your car's body/frame (with a sound engine of course).
There is no way in the world that oil is having this much affect on your car. Granted - different oils DO make your engine sound different (at idle and operating speed). But you cannot make any factual basis about your engine from sound and feeling alone.
Also... I have used a ScanGuage I/II for several years now. I drive 220 miles a day and I've done that for a year (Yes, thats over 60,000 miles in a year). Miles per gallon can be influenced by so many factors that unless you're running a ScanGuage and doing everything exactly the same ... you cannot make *any* assumption about your MPG. My MPG is NEVER the same as the day before. One day it will be 35MPG there and 39MPG back... next day it will be 33 MPG there and 36MPG back. Sometimes it varies up to 5+ MPG due to light traffic or wind direction and the cell phone idiot pulling in your lane. So... 1mpg loss is nothing to worry about.
I get basically the SAME MPG with Amsoil XL 5w30 (almost a 20 weight!) and GC 0w30 (heavy oil!). Wanna know what makes the biggest change in MPG? How I drive and how light I am on the gas and brake.
So yeah... ok back to eating lunch.
