Quote Originally Posted by avguy View Post
What was the code from the CEL? Likely unrelated, but perhaps it is. Do you have any idea how much sand is likely to be in the water you used? City water generally has less sand in it than well water. If it's likely to have a significant amount of sand, you might want to consider a full flush because sand can kill a water pump. Had you been checking the coolant level regularly in the 6 months since the T-stat was changed? If not, it could have been a very slow leak, and one of the usual suspects for slow leaks is the connecting hoses to the T-stat, especially if they reused the old clamps and hose.

I used city water but your slow leak suggestion is probably what it is I NEVER check levels, but i have been checking the last few days and water levels are the same even in the 90 plus degrees we have been having.

BM