Good idea on waiting after you hear air. I got the OEMTOOLS 8.0 Liter 24936 Manual Fluid Extractor from AMZ but I tested it with water first and it actually only holds 7.5 liters! Deceptive marketing if you ask me. The internal pump is taking up some of that 8 liter volume. Think I will return it and get the 10 liter Lumax LX-1314 which I initially had my eyes on.