car will not heat

[intrepidred1]

I have a 1989 chrysler and the heater will not heat, what is the problem?

[chevrolet1.8]

could be the thermostat stuck. if you remove it and lower it into a pot of boiling water you should see it move if not it's probably had it. they are not too expensive and normally come with a replacement gasket

[harley_Husky]

absolutely 'chevrolet.
i - Making sure that there is some coolant present...
(no coolant - no heat transfer to the matrix)

ii - Heater matrix (under the dash) pooped, normally accompanied by a wet carpet...

iii - possible airlock, but highly unlikely.

iiii - is the heater motor running when you turn the heater on....?

iv - check all of the above + 'chevrolet's answer.

Let us know.
Eddie