Coolent leaking but reservoirs are full

Over time, the dye in the coolant will stain the reservoir(s) causing it to look like its always full. Make sure you take the caps off the reservoir(s) and check them. If they are still full, check the "coolant" to make sure its not a petroleum product (aka transaxle fluid). Otherwise it just may be leaking too slow to be noticed at the reservoir at this point.

 

Well, red sounds like transaxle fluid but my idea of red may be diff than yours. The main thing is to make sure you're not leaking tranny fluid. If you really want to find the source of the leak, crawl under your car and look directly up from the puddle (follow the trail so to speak). You will likely see a drip forming from the source of the leak.

 

One of the first parts to begin a slow coolant leak is typically the ICE coolant pump. It will start weeping around the shaft seal. If you can shine a flashlight around the front of the engine toward the bottom you may be able to see a pink "crust" if it is the coolant pump.

 

Toyota SLLC is the only recommended coolant.

 

I am not certain on this as I believe there was a version for the gen1 prius, but you can buy it in concentrated form or ready diluted. Someone else will no doubt come in on this.

 

Toyota Long Life Coolant has the red color and is good for 30K mile service intervals. It has to be mixed with distilled water. This was factory-fill until around the 2002 model year.

Toyota Super Long Life Coolant has the pink color, is factory-fill for newer model years, and is good for 50K mile service intervals (100K miles for the factory fill.) It is premixed with distilled water.