2001 WS - thermostat or water pump problem?

[jaskho]

I just replaced a leaky bypass ("Y") coolant pipe. Before that it was running low on coolant for a while. I'm not sure how long since it never actually got hot by the guage, only noticed a problem from hearing hissing under the hood one day, and also started noticing the radiator fan turning on right when the engine got warm, which it had never done before.

So after the repair I filled up with water to test the system. Started the engine and let it run for about 15 minutes, waiting for it to heat up and open the thermostat. I kept checking the radiator hose for firmness (I assume that's a decent test of the thermostat opening up, assuming the water pump's running??). It never did get firm (and the temp guage stayed steady at "just right"), but then my radiator fan started up. That seems odd to me - why would it start running the fan when there's no water going through the radiator?

One other thing... as the engine was warming up, I had the cap off the overflow tank because I'd overfilled it. I noticed occasional glugs of water coming into the tank from the engine/heater. I'm hoping (and hoping and hoping) this means my water pump is working...???

Thanks in advance for any pointers/insight.

[jaskho]

I might have jumped the gun on this - sorry.
I ran the van again, and noticed that although the radiator hose didn't get FIRM, it did get firmer, and it got warm. So, nevermind

[wiswind]

"glugging" was likely air pockets working their way out of the system.
I know on the older windstars.....the water pump impellers are metal.....and I think this is the case on the newer ones.
So.....if the pulley is turning......most likely the impeller is turning.
I have read a couple places of certain Taurus (don't know which year(s) or motor, not 3.8L) that have plastic or nylon impellers for the water pump....and if the coolant is not kept changed as is should be.....it becomes acidic.....and eats away at the impellers......so the pulley is turning, but no fins on the impeller to move the coolant.
HOWEVER, this does not seem to be an issue for the Windstar.