My sister drove very slowly over a steep speed bump and the undercarriage was scraped, now it makes a loud noise like it has a broken muffler, the muffler looks fine though, what could it be? The car is a 2005 Chevy Cobalt.
Might be ESD rubber mats.
The pipes run deep enough underground that they don't freeze. That probably doesn't surprise you because your regular water supply doesn't freeze in the winter. The valve on the hydrant is down with the pipe, below the frost line. There is no water between the valve and the hydrant when the hydrant is turned off. If you have winterized your garden hose spigot, this is the same theory. You close the valve deep inside the house (deep enough that it doesn't freeze), and then you bleed out the air between the valve and the spigot.
