Originally Posted by Aero Blue
Let me run this by you guys then. I don't plan on driving my car during the winter at all, so what if I left the old oil in there. Its roughly going to be 7,800K and then change the oil in the spring and then put in my "extended life" Mobil 1 15w50? I never had a problem running heavier oil in the past, but with all this tolerance talk, its got me thinking a little bit.
If you're going to store the car for the winter, change the oil first! Moisture combines with combustion by-products in the oil and will form acids that will do nasty things to your motor.
Why would you want to run 15W50 in that engine? The mechanical tolerances are so close that it needs a thin oil to get lubrication everywhere. If you start running that pancake syrup sooner or later you're going to spin a bearing or score a cylinder and then your beautiful Crossfire will become a lawn ornament because you're not going to be able to afford a new engine and there's no way DC will honor the 7/70 powertrain warranty when they see you've been running the wrong oil.
Quit being cheap and use the oil that the engine designers told you to use.