am posting this in case it might help someone else diagnose a similar problem.
94 sentra had a small but annoying oil leak underneath the engine. engine oil was from front to back and up both sides of engine, even up the forward side of the auto transmission. could not see oil coming from behind the crankshaft pulley, but found oil behind the oil pressure switch grommet. replaced oil pressure switch, did not stop oil leak (had previously tightened oil pan screws). while i feared that the rear crankshaft oil seal might be leaking, i chose to replace the front seal first. upon removing pulley, found a drop of oil hanging from the seal. noticed the pulley had the grove worn in the part that contacts the seal. replaced seal but seated the new seal 1/16 inch from previous position (to avoid the worn grove). btw, the rope trick did work (found that i had to feed the rope through a supporting plastic tube to keep it from kinking when pushing rope into the cylinder).oil leak stopped.
btw, no need to try my email, the swen/worm.automat.ahb virus keeps my yahoo standard account overflowed, even with daily emptying and using yahoo's primitive filters. some of the emails are originating from apparent asian sources.