Chuck I've found them to be from 6 to 8 gallons, depending on oil pan and etc. I just start by putting 6 (using part of 1 of these to prefill the filter) in and checking it, if it's up in the safe area chances are your good to go. But to be sure fire it up let it run till yer air builds up(just a time frame I use), shut r down and wait about 5-10 minutes and recheck it! That's how we do it around our shop but since this is your personal coach you'll know exactly how much it holds after the first time!
