Hehe this is old, but I just saw it.

I didn't have any leaks at all. The GM service manual says to throw in two of these pellets whenever the system is totally drained.

I did manage to check my coolant sensor. It did have some buildup in it. I have cleaned it out and still have the low coolant light almost every trip. Either my sensor is crap or I may have an electrical issue. I have unplugged it to see if it comes on or flickers...if not, I'll buy a new sensor.

 

Just pick up a new one from Rockauto.com and save yourself the trouble. Mostlikely cleaning it wont do the trick as they get deposits and build up on the sensor rod and go bad. Poor design by GM.

 

mine went away after i cleaned the ground contact for the wiring...ended up grounding my MSD box and electric water pump at the same spot, and all has been well ever since

 

Mine went away after I drained and flushed the coolant. It wasn't low, but the water was over 5 years old and was black. It stunk really bad as well. Once I put in the new stuff I had to top it off again after a few miles of driving. Now the system is full and the light is off.

 

Black, stinky coolant is not so good......