Volvo 5.0 GL-E and oil dipstick readings

[Railslider]

Hey everyone, first time poster. Bought a used boat last week, went to do an oil change and I'm having some concerns. When I started, I noticed the stick was reading a little overfull. Started the boat, ran to temp, and sucked the oil out with a lousy pump I will not use next time. I purchased an extraction pump that has a little tube that runs down the dipstick tube instead of the Jabsco or other varieties that screws onto the dipstick tube. I sucked out 4 quarts before I could not suck out any more oil. Installed new filter, added 3 quarts of oil and the stick is reading slightly overfull again but I suspect the filter may pull it fairly close once I do fire it up.

My question is this - using the pump I used, is it safe to assume I didn't extract all the oil from the pan? I'm assuming the tube from the pump ran into a baffle in the pan and that I didn't get all the oil out, so that by adding 3 quarts I actually am full. I would hope that there are no discrepancies with the dipsticks - full means full and low means low? Is it safe to trust the stick 100%? I can't just dump another 2 quarts in, that's against my conscience at this point. Thanks everyone!

 

[dypcdiver]

Sick your head down and look where the dip stick tube runs, or if you can't see take a photo with a phone or camera. By sucking the oil out from the top of the dip stick tube you get all the oil out. By putting a flexible tube down there you cannot be sure that it doesn't get up into free air inside the sump. That is why VP designed it to be pulled from the top of the tube!