Ok. I was driving and i noticed the temp start to climb. I pulled over, turned off the car, popped the hood, and saw that all of the coolant was leaking out of the radiator drain plug very fast. All of the coolant leaked out of both the radiator and resevoir. I let it cool down and my da brought me more coolant and got myself home. When we were filling up the coolant after it leaked out we noticed that the drain plug was striped out some how. After i got home i took out the radiator and replaced the drain plug in it and figured i would change the thermostat at the same time. After i finished and filled everything up, I let the car warm up. The upper hose heated up showing that the thermostat is opening, but when i squeeze the hose, there doesnt really seem to be any pressure even with the thermostat open. THe water pump is a stewart components stage 1 pump that i just installed in may. What could have caused the drain plug to just pop out?

Thanks

 

I was gonna ask if you'd recently done any work on the cooling system, but I see that you have. So my guess is that back in may, you probably stripped the drain plug when you tightened it up, or you didn't tighten it enough. It's probably been leaking tiny bits since then but you haven't noticed.

I had a tiny drip for a loooooong time, but I could never find where it was dripping from. Then right after I did a coolant change, it still dripped, but then I could see it was dripping from the plug. I couldn't get the plug tight enough to stop the dripping, so the predictable happened when you force-tighten plastic, lol. It stripped and broke. And of course, the broken piece was inside, so I had to pull the radiator and dump out the piece.

 

That seems like it probably was the reason. Why couldnt they just make it out of metal like normal. Stupid plastic. Anyways, I do have pressure from my water pump so everything is fine. Thanks.

 

It's not the water pump that builds pressure, rather the expansion of the heated coolant. If you ran the engine with the cap removed after the refill, then you wouldn't have seen any pressure after replacing the cap until the next cool/heat cycle.