Just replaced the stat on my Seville. Heater worked for one day through vents, but now back to defrost mode, yet has hot air. Just noticed a small amount of coolant leak. The leak is on the side of the engine where the serpentine belt is, which I just replaced, and the coolant is getting on the belt. I did not add any coolant pellets when I installed the new thermostat. I did it on a cold engine, opened the radiator cap, removed the old stat and replaced the new one. Topped off the radiator and over fill tank with coolant. I'm running at about 205 degrees average, which is alot higher than it was before the new stat. The old stat was stuck open. Now the system is properly pressurizing but has a coolant leak. If by chance it is the water pump leaking, will the pellets stop the leak??