I changed the engine oil, coolant, and power steering fluids this weekend for the first time in my 2005 DB9. Never had a vehicle harder to work on than this. I filled it up to 11.5 quarts and saw the oil level at midway between MIN and MAX. However, I had just started the car and moved it forward a bit in order to let the oil filter fill with oil. Thought I was good to go and came back about an hour later to check and my oil mark had moved to above the max mark! So I removed about half a liter to get it back to mid mark where it stayed, in that bay at least. In my other bay, now it's reading above max again even though the slope of the garage is very similar to the other bay. This is ridiculous that a car holding 11+ quarts of oil can be so easily swayed on its dipstick. I'm pretty sure most of us without garage floor drains don't have perfectly level garage floors (to allow water to run out of the garage). I've included a picture of the slope of my garage for reference.

Having only put in 11 quarts, I'm pretty confident I am not overfull. How do you guys ensure a perfectly level car to check your oil?

Now to give back, what I learned was to follow Aston's advice on checking the oil. I'll attach their service bulletin at the end of this message. I tried three separate times starting the vehicle and then checking the oil, and each time the oil level reading lowered roughly 50% of the way between the MIN and MAX mark after the car had been started or moved, giving me a false low reading until I let the car sit untouched for about 30 minutes, as Aston states. For those new to these vehicles, I'd recommend heeding that advice or you'll get false readings like I did. Let it sit for 30 minutes, make sure the oil is cold, and check the oil that way.

Picture of garage slope:

Slope of garage. Car nose to left (slightly higher).

 

I don't know if all Astons are the same, but my V8 Vantage has a dry sump, and the owner's manual recommends checking the oil level after the engine has been run for 20 seconds. Below is the procedure.
"1. Operate the engine at 1500 - 2000 rpm for 20 seconds then set the engine to OFF.
2. Wait 30 seconds then remove the oil reservoir cap and wipe the dipstick clean with a lint free cloth. Replace the cap and fully tighten.
3. Remove the cap again - avoid contact with the sides of the tank. If the level is below Max., top up to the Max. mark with the recommended engine oil.
Approximately one litre (two pints) is required to bring the level from Min. to Max.
4. Repeat from step 1 to check the level."

When the oil is changed, it recommends that some oil appears on the dipstick before starting the above procedure - see below: -

"Make sure that there is oil in the reservoir before the engine is started. Look for a sign of engine oil on the dipstick. Running the engine with no engine oil in the reservoir can cause serious engine damage."

 

V12 is wet sumped. V8 procedure is not applicable.