2001 Toyota Celica

2001 Toyota Celica GT
84,000 miles
not sure of engine size

My daughter's car has been having heating problem. Sometimes it works and sometimes it doesn't. It will throw out heat while she is moving but when she is idling for any amount of time, it will run cold. We have changed the thermostat and was told that the bottom hose was staying cold. She has never overheated. She hasn't changed her serpentine belt. Could this be slipping at times and causing the problem.
March 5, 2007.

They made it sound that the radiator is clogged-try this remove the Stat and go for a test and see what happens and comeback.

Could be a heater control valve at the heater hose. And again it might be an entirely different issues.

Mar 5, 2007.
Check the heater contol valve-also try this remove the Stat and recheck for heat.

Mar 6, 2007.