I have a 97 Lumina. 3.1 v6. I've recently experienced overheating and coolant loss. When it sits there's no puddle under the car. No oil in the coolant or vice versa. No leaks from hoses. Today I looked under my car and saw this. This one's on the bottom of my radiator on the passenger side, and there's one on the drivers side. The other one is dry. This one is wet. Can someone please guide me on what this is? I'm not totally mechanically ignorant. I can change plugs, wires, oil, and other small things like that, but I have no clue what this is.

 

Hello, I've had the same problem but I just checked out all the hoses and clamps and the cap from the radiator to coolant reservoir and found that the clamps were worn out and leaked very minimal coolant from it when the engine gets hot (maybe because of pressure build up. Since the Right bottom side of the radiator is wet there should be a small leak around the right side where the coolant is circulated. Also i would check the water pump for any leaks i also had changed my water pump and it leaked from there. Hope you can get it fixed