sounds like you are the victim of a crooked saw shop. if it pumps oil the pump is still good. they likely didn't even replace it but billed you for it. gotta be careful with some of the crooked dealers. some insanely worn pumps will leak a tad out the worm gear housing area but i mean it would take some major hours. i've only ever seen it happen to a 395. other then that the pickup hose going into the tank is the seal for between the tank and the pump, very rare that that gets damaged but could be as for it to drain the whole tank it would have to be leaking somewhere low. other then that there is a rubber grommet that seals the oil tube to the pump. this is most likely spot for most saws as a large number of saws will leak there eventually. they usually only drip from that spot of a few hours after use though. the other rubber fitting is just to secure the other end of the tube to the bar mount and will almost never fail. i've seen some dip ***** forget to reinstall it after working under there and had it leak something fierce down behind the clutch. replacing the rubber bits almost always cure any leaks for me. i got a 372 i bought new in 03 that has never leaked and i've never replaced any of the rubber bits but i got a 372XT from 2012 and the thing pisses me off. all the rubber bits are good and yet somehow it dumps oil out around what looks to be the adjuster screw threads. only does it for about an hour after last run though. thinking i'm gonna swap a 390 oiler in it anyways. another possibility is having it leak out the tank. if you are talking it leaking bone dry from an upright position the case gasket could be culprit or even case damage as well but less likely. from a not being there to diagnose guess i'm putting my money on a split pickup tube. the dealer could replace the pump even and if that hose is split at the sealing cup it will always leak.
