Sounds like diesel fuel. Look real close. It is obviously coming from the injector somewhere. If it were coming from the cam cover it would be black.

Whats this inj. leak?
 

Any idea what is causing this leak? its a clear oily oderless substance. None on the injector or hoses, not coming from the cover gasket.

Hi wallknight:
Did you by any chance change your oil lately? or added some oil lately( may be topped it off at gas station). To me it looks like you might have poured some oil on Valve cover which then rolled down to the area where it is. I see a flow mark ( I think) on the wall of valve cover behind the injector.

I think try cleaning it completely and then turn on you car and see where its coming from. If it smells diesel its for sure injector or the smaller diesel lines that run in the backfrom one cylinder to 2nd to third etc. I had one of that line leak on me once but it smelled like diesel.
Your odorless description throws me off.

MVK

Although it wouldn't be clear, An injector can loosen up and it will leak like you see there. They torque to 55ft.lbs.

...or one of your bleeder lines has perished...