Originally Posted by Rusty

Look at you reservoir. Where is the coolant level at? Is the tank full, half full, empty?

1. When the shop installed the temp sensor. They could have spilled coolant from the location. And it collected on the under tray. When you drove the car. It moved and started to drip.

2. The coolant is leaking from the temp sensor.

3. When the shop finished the temp sensor install. They over filled the reservoir and the extra got blown out of the overflow hose.

Keep an eye on your reservoir if you are driving the Z. If the coolant level doesn't change. I say you can rule out a leak.