rwd said:
What's the best method for getting all the old oil out? Jacking the rear up to make it level?
On my C4 cars (L98 and LT1) I put the front of the car on jackstands and the oil drained completely. I have a tank that has a clear plastic gauge on the side so you can measure what comes out, and if you dump the oil from the old oil filter in it came very close to five quarts.
I can't use my floor jack on the Z06 (it's too low) so I haven't been able to change the oil myself. The Chevy dealer did tell me it takes longer to change the oil on an LS6 because it takes more time to drain. I don't know whether that's true, or whether that was just his way of saying there were cars ahead of me for oil changes.
One point where you may get differing opinions is on whether to run the engine for a few minutes prior to draining the old oil. The logic supporting that technique is that this makes the oil warmer and therefore less viscous allowing it to drain faster.
On the other hand, when you do that it seems as though you are putting oil back up into the valve gear in the heads, making it take longer to eventually drain back down into the pan and out the drain hole.
I don't start it before draining, on the theory that if the car sits for a long period the oil drains down into the pan and thus you get more of the old oil out.
I should point out that I live in Southern California and it never gets cold here and I use Mobil-1 5w30, so it's not as if the oil has the consistency of maple syrup after it sits overnight. In colder climates it may make sense to warm it before draining it.
One tip I picked up years ago is to fill the new oil filter with oil prior to screwing it in. This reduces the time it takes to get oil circulating back through the filter and minimizes any scuffing due to not having enough oil available when the engine cranks for the first time after the oil change.
Ray