I could smell antifreeze leaking out somewhere from the engine when it got warmed up. I jacked it up and checked underneath and looked where the cylinder head is bolted to the engine block,

I could see a small amount of green antifreeze seeping out, it was dark and thick as it had been leaking for a while so it kept evaporating and ended up being a wet, dark green stain or buildup over time. There is no way you'd see this unless you specifically went looking for it, or smelled the antifreeze leak as I did.

I looked it up on the net and found that is a common issue on these. Took it to the Local Dealer and they installed 1 new head gasket, apparently it's more common on one side than the other.