Are these symptoms of a bad thermostat?

I own a 1999 Ford Explorer but my wife is the primary driver of the vehicle. A few days ago she was on her way to work and left a huge trail of anti-freeze behind her. Later that day I checked the system for leaks and found what looked like a leaky lower radiator hose. I removed the hose to change it and upon inspection there were no tears. I reinstalled the hose, figuring the clamp was not seated properly, and the leak has been gone ever since.



I drove the Explorer today to make sure it is working properly and the temp gauge constantly goes above the center (190 degree). Today, it actually started drifting to the overheat position on my 5 minute ride home. When I got home, I left the car running and squeezed both hoses to feel for good flow. The upper hose definitely had good flow. The lower seemed like it had good flow also, but I'm not 100 percent. The line was pressurized but it got so hot under there I couldn't get a good feel for the flow. A bunch of coolant did come out of the hose while it was removed.



Could this be signs of a thermostat going bad? The only other thing I can think of is a bad water pump and that's only if I was wrong about the coolant flow in the lower radiator hose.
Are these symptoms of a bad thermostat?
The odd thing is that you said it lost lots of water, but you never said you put any in or checked its level?

You really should have.



If you are at all in doubt about the thermostat, then change it.

It only cost $3.

It should not take more than a few minutes I would guess.



The way to test a thermostat is to start with a cold engine.

Touch both radiator hoses, and they will both be cold.

Start the engine.

One will slowly get warmer. That is the return side that does not have the thermostat.

The other side should stay cold until the engine reaches proper operating temperature, and then instantly get hot.

It both get warm slowly, or the one delays too long before getting hot, then the thermostat is bad.
Are these symptoms of a bad thermostat?
yes, water pumps rarely stop working, they just leak.