I have a 1999 escort zx2 that I just rebuilt the engine in. It seemes to have an illusive oil leak. It drips off the the bottom of where the engine meets the transmission and would appear to be the rear main. The problem... I have replaced the rear main since i rebuilt the engine in a attempt to fix it. It still leaks. There is no obvious trail of oil running down the block or from anywhere for that matter. The crankshaft is a brand new reground crank so there is no problamatic wear groves. Any ideas on where to start looking?
Note: The last rear main i pulled out seemed to have the spring knocked off. The new seal was replaced with help from a 20 yr ford mechanic (my uncle) so the spring was not knocked off from installation.