Originally Posted by Rob
First off, you can use M1 extended performance for 15,000 miles. The catch is that you MUST change out your filter every 5,000, or you will overflow the filter and cause the dirt and impurities to enter back into the system. That is the main reason why it looks like it could not hold it's own for 15,000 miles. It will be the same with Amsoil.
Also, you can have synthetic oil sit for 7 years and have it be fine. It will not change one bit. You can not base synthetic oils off of years, but ONLY off of milage. For all what you know, that car could have just sat in the shop for 7 years. Also, im not 100% sure on this, but wern't synthetic (atleast full synthetic) oils a recent discovery like 5 years ago? One more thing, I'm not up for sending in a collection tank to Amsoil everytime I need my oil checked. Shipping alone for those type of contaminates "legally" must be up in the 30s to 40s anyway. It would be best to just go ahead and get fresh oil into the system.
Well.. we will see, it say's on the back of the bottle i am holding in my hand that the oil is good for 25k miles.. i will change my filter accordingly and report back in about a year or so.. lol.