I have a 1995 Buick LeSable (3.8) that has developed an engine oil leak.
The leak is a steady drip, 1 drip about every 4-5 seconds, that runs off of
the oil filter. It only leaks when the engine is running. I checked the
oil filter gasket and it was fine. I suspected the oil filter adapter
gasket, as the oil seems to run down the edge of that gasket, so I replaced
it. The leak continues. I suspect the only other possibilities are the
front crankshaft seal or timing cover gasket. Is this type of leak typical
for this engine? What normally causes this leak?

Thanks, Steve