Overheated and blew coolant out of expansion tank

[broncobilly69]

I have a 2000 SOHC 4.0L Explorer. I was driving today noticed the temp gauge was high, pulled over and popped the hood. I could hear bubbling or boiling water and the expansion tank was full. I carefully pulled the radiator cap off, nothing. I noticed a few bits of blue teflon under the cap.

I filled it with water gave it about ten minutes to cool down and got home as fast as I could. No hiccups on the way home. Temp gauge rose a little bit but then went to normal.

I assumed the water pump has failed because of the teflon but didn't notice coolant coming from it (weep hole). The quick temp change after driving home could have been the cold water or a sticky thermostat.

Any help would be appreciated. I'm debating whether or not to start tearing it apart to look at the water pump.

 

[swetrid]

Thermostat is the normal overheating problem. Sometimes the thermostats separate and pieces end up in the water pump but usually lock the water pump and throw the serp belt off.

 

[windsors03cobra]

Very very rare to a water pump to stop pumping water, water pump failure is usually bearing and seal failure resulting in the leak from weep hole and or other places depending.

Sounds like the thermostat. Maybe the blue "teflon" is blue permatex silacone ? Maybe from a previous water pump or t-stat replacement.

 

[broncobilly69]

Ok so I spend last weekend changing the thermostat and some other unrelated items. I haven't had the problem since but the temp has been running below normal. It seems to have been the thermostat.

I was also having problems with the A/C cycling on/off and then just off. That has also seemed to fix itself. Its now having the issue of switch from vents to defrost. I haven't looked into yet but I'm pretty sure thats been covered.

Thanks for your help.