The heater core is difficult to change on the Ford trucks. They have it buried in the plenum box and you have to remove the steering wheel, steering column, dash, evacuate the refrigerant system, drain the radiator, and remove the plenum box to get to the core. Replacing the core is easy, getting to it is a day's work. The Expedition is particularly difficult to get to. It is almost above the transmission tunnel and well buried behind the dash. The Expedition uses the same plenum box as the F150, so any information on that system applies to the Expedition/Navigator.
You need to be sure that the heater core is really the problem before tackling this job. If you have a pool of coolant on the floor, you'll have to go after the core. If the problem is lack of heat, there are some things you need to eliminate before tearing into the truck. You need to make sure that coolant is flowing through the core. Check the temperature of the heater hoses going into the firewall when the engine is cool and see if they warm up together as the engine warms up. If both hoses get hot at about the same rate, this is a good indication that coolant is flowing through the core. You can also remove the hoses and flush the core with a water hose splice from Home Depot and a water hose. Water should flow unobstructed through the core.
If it appears that coolant is flowing and you don't have obvious leaks, the next step is to check the blend door. This door controls the air flow through the heater core and failure is common on Ford trucks. When the door breaks, it can block the flow of air through the core and kill heat and will also have an impact on AC. If the system seems to work intermittently, it's a good indication that the door is broken and rattling around randomly blocking or opening the passage to the core.
For diagnostic information on how to check the operation of the blend door and a cheap easy fix, check the heatertreater listing on Ebay or the web site at heatertreater.net. The dealer fix for the blend door is basically the same procedure for replacing the heater core, so it will be expensive. The HeaterTreater alternative will solve the problem at a fraction of the cost and work and is well within the capability of the average shade tree mechanic.
Instualation of a heater core on a 1999 Ford Explorer V6, how do you install the heater core.
What's the best way to change A DASH heater core in a 1999 ford expedition ANSWERE: Its a long process, but I found instructions at the Queegebo website site. They are very good and walk you through step by step with pictures. Here is the link. http://www.queegebo.com/articles/cars--other-vehicles/heater-core-replacement-instructions.html
How do you replace a heater core in a 1998 Ford Expedition?"
heater core is in back of the glove box
You have to completely remove the dash to get access to the heater core.
To change the heater core on a 1999 Chevy 4-wheel drive, first remove the dashboard and drain the coolant. Unbolt the core from its mounts and remove the dash panel to be able to change the heater core.
How do you replace a heater core in a 1998 ford expedition?"
You have to remove the entire dash board to gain access to the heater core.
the HEATER CORE can be removed by removing the dash. how do i ghange the dash
Its a Durango.......not a Drango.
how to remove the lines from the heater core on a 2001 expedition
The 1999 Chevrolet Z 71 heater core can be accessed by removing the passenger side kick panel. Remove the heater core water hoses. Remove the heater core retaining bolts. Reverse the process to install the new heater core.