I have a 1991 Trecel with a bad oil leak I replaced the front seal didnt help thats where oil leak is worst and leaks twice as bad if oil level is on full mark

Have you looked in timing belt area? cam seal may also be leaking, coming out at lower pulley.

spray the engine with a bit of solovent, take it for a quick spin, then check. if its loosing oil that fast, and you don't got blue smoke, its coming from the crank case area, like tercel GTS said in a way. but remember, its not always the compilcated crap...check the oil filter seal, might not be tight enough. oil pan seal, and blahbity blah. it may be a crack in the block, but i doubt it. but if you wana know for sure, go buy some oil dye cubes and a blue light, put the cubes in your oil, run it a bit and check the engine with the blue light. any oil that leaked will show neon green under the light.

possibility check dipstick o ring could be worn and leaking out of dipstick.

THANK YOU!!!, i had this problem for ever i finaly got tired of seein oil in the drive way so, i have the oil pan seal, oil pump seal, crank shaft seal, repaced and it tuns out the dip stick was loose and needed a new o-ring. But now i am getting a leak betweent tranny and engine, it is eith rear crankshaft seal or rear main seal.