Does anyone know how to fix heat in an 87 fox lx. I replaced the heater core and the thermostat and its still not working?

 

I just went through this with my 97. I replaced the thermostat and it got luke warm. I then replaced the Coolant Temp Sensor. Now it gets hot. Try that and see what happens. $20 for the temp sensor at Auto Zone. Temp Switch could be a possiblity.

 

Alright i will give that a try. thanks for the help.

 

Have you checked yet to see if you might a small crack in the plastic lines or a split rubber boot that comes from the Vacuum Distribution Block to the small vacuum manifold -for a lack of a better term- next to the right hood hinge on the firewall.
Or from that manifold to the heater, or from that manifold to the A/C vacuum reservoir in the right fender ? Without a vacuum the heater won'y function properly to the different vacuum solenoids.