Mystery Coolant Leak 2012 Prius II

Yesterday I noticed a small puddle of pink coolant on the garage floor under the aft wheel well on passenger side of car. Further inspection showed similar small puddles on the floor under the passenger side of car up to the front wheel well. I opened the hood and removed the bolts holding the reservoir and checked for any coolant under the reservoir. It was bone dry. The coolant level in the reservoir indicated it was full. No leaks at the small hose on the reservoir. (I drained and refilled the coolant a couple years ago along with inverter coolant and also changed the CVT fluid.)
I removed the under engine panel to further inspect for leaks. Nothing found. Over night the garage floor shows no leaks anywhere. Now I'm at a loss to find this mystery leak. Anyone have any ideas where this coolant could be leaking from? Also this car is always parked inside my garage where temps are above freezing and not outdoors for long periods of time so I don't suspect a freezing issue. Thank you all in advance very much!

 

Hi Mendel. In my case, I am using a winter blend windshield fluid that is blue. I will also remove the coolant reservoir cap to release any vacuum if it's present and see what happens. Just a thought. Thanks for your reply!

 

Yes no kidding, where coolant had dripped from the rear wheel well leaving a small puddle, you'd think I would easily find its source. Also had some small puddles as well all along the side of the car, on the floor, front to back. It is pink.
I just drove the car long enough to get up to "normal" operating temp, pulled in the garage and looked the engine bay over as best I could and underneath it. No coolant that I could see. I thought perhaps it maybe leaking around the water pump, thermostat/inlet hose or ?? Noticed the coolant in the reservoir still cold. I thought it would be hot. Not sure if that's normal? Removed the reservoir cap with a psft sound Found no leaks. I didn't taste it but it smells like coolant (yesterdays puddles).
I'll continue my small trips around home and see what happens. I did make an appointment at a local shop I know of for next Tuesday but may cancel if no further leaks. He wasn't overly excited about taking in a "hybrid" vehicle. That is usually the case around here outside of the dealership. Dealer won't help unless I bring it in to their shop. Thanks again for your replies!

 

Thanks for your reply! First thing I thought was a bad water pump, thermostat, or heater core. I have no clue where they put that heater core but I did feel around the floor carpeting under the dashboard. Anyway I won't reinstall the engine under cover until I'm sure the leak is gone. That reminds me to pull the dipstick and look at that oil on it. So far it's a mystery.

 

If the head gasket was blown wouldn't I see muddy looking oil on the dipstick? In other words coolant mixed in with the engine oil right? Thank you!

 

I haven't noticed any performance issues. Only drove it a few miles Yesterday. Temp came up normally and heater temp worked OK. The outside temp was about 30 degrees Fahrenheit. No warning lights on dash. The exhaust pipe is dry and actually pretty clean. I have about 91,000 miles on the car. 2012 Prius II The oil on the dipstick is normal looking as I just did the 90K mile oil and filter change. I looked over the engine again this morning and do not see coolant leaking anywhere. Strange stuff I tell ya. I'm thinking I will have to take it to the dealer and have them check it out. That's a scary thought. Local shops are afraid of hybrids. Thank you for your reply!

 

The Car Care Nut and Eric at South Main Auto are two of my favorites on YouTube. Both are exceptional mechanics with years of experience. I still have yet to identify the source of the leak albeit the fact that I haven't driven it much. I just can't imagine this car having a blown head gasket at just over 90K miles. I talked with a guy who rebuilds the hybrid batteries in my area a couple years ago and he suggested then I pour 2-3 ounces of Steel Seal directly into the radiator via the reservoir hose as a preventive measure. I did not do that and I am not sure that I will. I've heard it can damage small coolant pathways and clog the same. Since I can't say for sure I have a blown head gasket I don't want to introduce more problems. I'll keeping watching for any coolant leaks. All along I thought maybe it was a bad water pump or thermostat, maybe even a defective hose, but the car appears to run well without overheating or being abnormally cold. I do not trust driving it very far from home. Thank you for your reply and advice.