I started a thread a week or two ago called "Want pond to go bye-bye" or something to that effect. Same problem, except mine's mainly on the passenger side.

The weirdest thing is I got a bit of water there last weekend, with no rain in a long time...but I was on a long trip and I think a water bottle leaked.

The place I was told to check was the drains at the back of the engine compartment along the sides. I'd suggest looking at the thread I started for more detail, as I don't remember the specifics myself and will need to review the thread before I actually go and clean out the drains.

Just some thoughts...good luck!