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I was wondering what some more mechanically inclined people thought about the issue I am observing on my 2000 Civic EX.

My car has about 156k on it and is stock. Sunday before last I had the oil changed. Monday, I drove to work and back. No issues noted. My commute is about 95 miles round trip, mostly highway (and that day kept highway speed most of the time). I got home around 5. I walk around the front of the car to leave the garage, and didn't notice anything amiss. Came out around 7 and I had oil seeping out from under the hood right next to the driver's side headlight and running down the bumper. Popped the hood and oil was all over the right side of the engine bay from the master cylinder to the front. Didn't notice any oil on the valve cover, front, or back of the block. Looking at the underside of the hood and the interior, it appeared that the oil was under pressure, spraying up against the hood and out towards the driver's side of the car. It looked like the concentration was towards the front of the engine compartment. I brought it over the shop that did the oil change and they said they couldn't see a spot where oil was coming, even after cleaning things off a bit. The level was still good, so it didn't loose a whole lot of oil. They replaced the oil filter, thinking it might have been bad, but I don't think the oil would be limited to the right side of the bay if it was the filter.

So I went away for Christmas, and put new cardboard under the car to see how much oil leaked (it has a small leak from the pan that I know about) and there didn't appear to be much leaking from Wed. to this morning. I drove in this morning and when I got to the parking garage, I noticed a bead of oil that had come out of the hood around where the headlight and grill meet (same spot as where the "leak" was last time") and was pushed up the hood from highway speeds. Same thing when I got home tonight, and there was a bit starting on the front corner of the hood, again on the driver's side. I popped the hood and wiped down some areas where there was what appeared to be fresh oil...there wasn't a lot. Again, the level seems fine. Looking around the block, the exposed belts appear to be free of oil, there is some build up on the lower part of the timing belt cover, the exposed top section is clean. I see what appears to be fresh oil in the grooves of the cover. Unfortunately they are in a tight spot to try and clean off and observe.

So any ideas? I am not sure what would be pressurized, build up on the underside of the hood, and seemed to first present itself when the motor was off. If it is a slow leak from somewhere, is it kosher to just keep driving with it and checking the oil every few days? If it is a cam seal or something it might not be worth the expense of fixing, but a cam seal shouldn't be getting outside of that timing belt cover right? Also what could be the cause? I know the car isn't new and seals go bad, etc. but it is fishy that this happened right after an oil change. Could overfilling cause it?