I have a 99.5 with the 2.8l engine. After letting it sit a couple of days, I came out and it had dumped maybe 1/4 to 1/2 quart of oil on the floor of my garage. I did some initial searching and replaced the oil cooler o-ring since that seems to be a common source of leaks. I ran the car for a bit, and the leak persists. The oil is running down the front of the engine, from above the the lower oil pan seal so that's not the source.

I don't think it's the valve cover gaskets as they were replaced about 10k miles ago with the timing belt. From the top, everything looks dry.

Any ideas what to check next? I can't see much else without removing the radiator. I'm willing to do that, but if it's just going to narrow it down to one of a couple major repairs then I might just take it to a shop.

 

Here's a little more info--the car does not seem to drip any oil while it's running, but when I turn it off it drips heavily down from the front of the engine.

 

Possible places it could leak oil on the front of the engine:
Camshaft seals
Camshaft tensioner gasket and halfmoon seal
Oil cooler
Oil temperature sensor
Crankshaft seal