Heater fan only blows cold air replaced thermostat did not help any suggestions 1999 ford taurus

What have you checked so far ?
Radiator full of coolant ? Heater hoses getting hot ?

unless it is the heater core which you should flush system,,i always boil my new thermostat to make sur it compresses

sounds like your thermostat is stuck open, if its takes a very long time for the engine to warm up and you get nothing but cold air from your heat then thats the first place i would start.

replace your thermostat and flush your system

It could be air locked. Feel both your heater hoses, and, with the engine running, loosen the one that's cold, if there is one. If that doesn't help, it is probably your heat control valve that is malfunctioning.

have you recently replaced your waterpump ?

ford you say


check that there is flow coming out your heater hoses
step 1 remove 1c heater hose
step 2 have a friend start car remember it is easy to install a heater flush valve and it makes the job easier
if there is flow then eithor you have a blockage or an air lock
if there is no flow there might be a valve in the heater lines to stop the flow of coolant to the car when ac is on i have seen theise in a few cars but they are rare if there is a valve than make sure it isnt frozen with rust and ir does work in a ford i would assume that it is a vacume valve

good luck and happy hunting

Try checking the two pipes that go into and come out of the heater matrix, is one of them hot? if it is there is an air lock within the matrix, Also is the thermostat opening fully? Sorry i know you said you have changed it twice already but take it out check settings when it should open and close, then boil some water and test the thermostat

The problem was a vacuum line leak. Replaced the line.

sounds like the controller went bad use temp checker see what your temp is at inlet of heater core from hose