the rear main oil seal housing, and the oil pump have grooves
the sump doesnt in these places.
sump has grooves on the straigt ends.
there is no easy way to get sealant off bottom of block, only thing i can suggest is to use a decent scraper and elbow grease.
I'm having this problem with mine
Im thinking of having a crack at it myself this weekend.
Do i just literally jack the car up & whack it on axle stands..then drain the oil & undo all the sump bolts and remove the sump... then clean up all the edges as per Texx's info above, then use some locktite instant gasket (plenty of) all the way round, then shove back on & wait for a while?
yer but let the sealer go a little bit tacky and then screw it back on and tighten it up evenly till bits of sealer come out all the way round the edge - it can be a pain in the arse but if you do it cleanly with plenty of sealer you should be fine
most important though is to get all the old sealers off
well it depends how well it was stuck on last time lol - i cant remember weather or not you need to take the exhaust off the down pipe or not to get it off.
but all in all its not too much of a major job - it shouldnt take you longer than an hour and a bit !!
I thought Toyota supplied a composite gasket for the sump? I used the one that came in the engine build set and it seems to be working well, so far.