My thermostat needs to be replaced on my 93 Ford Aerostar. The Ford dealership quoted me $210.00 to replace thermostat. What a joke! I would like to try replacing it myself. Can one of you guys provide me with instructions on replacing thermostat? Any assistance would be greatly appreciated.


Sincerely,
JA

 

I'm sure you will get some good advice here. However let me give you a couple of pointers. Your first step should be to use the search feature. The steps are most likely here already. Second be sure to give the year and the size of your engine. The 3.0 and 4.0 are different.

Oh and welcome to FTE. I think you will like it here.

 

Go to Autozone/Pep Boys etc. and spend the 15 bucks for the Haynes manual for your Aerostar. Then read the instructions for changing the T-stat.

 

The manual makes it seem deceptively simple. On the 4.0 engine here are some tips:

A.) A set of 1/4 inch drive sockets are handy, but 3/8 inch will work. A 3 inch extension is necessary for a 10mm socket.
B.) An alnico magnet small enough to fit inside a 10mm socket will greatly aid removal and installation. A 10mm deepwell socket works best if a magnet is not available. (see below)
C.) Put a rag under the immediate area of the outlet housing to catch loose bolts and sockets.
D.) The rubber gasket does not come with the thermostat and must be purchased separately.

1. Remove the air tunnel and the plastic weather shield attached to the throttle body. Both items use a 5/16 inch socket.
2. Release the serpentine belt.
3. There are two black metal heater pipes running in front of the thermostat housing area. There is a clip holding the two lines together and just a little way further down is a clip that secures the pipes to the engine block. Remove the screw (5/16) on the second clip. Find about a 12 inch piece of coat hanger or similar. This will be used to hold the pipes out of the way during portions of the operation.
4. There are three bolts holding the thermostat outlet housing to the block. Two can be readily found. The third is located between the outlet elbow and the belt tensioner. There is also a wire loom that runs in front of the bolt head which makes it difficult to both see and access. CAUTION - You can push the wire loom out of the way to insert the extension/socket but the wire loom tends to bind your socket when withdrawing. The upshot being the socket gets pulled off and it drops into a black abyss of engine components. You will spend a long time trying to recover it.
5. Use the coat hanger wire to pull the dual pipes to the right to allow better access to hidden bolt.
6. Once all three bolts are removed, pull the outlet housing forward to expose the thermostat. Note the orientation of the thermostat. The small air vent is at the 12:00 positiion and the spring goes toward the engine block. There is a rubber gasket around the themostat. No other sealant is necessary.
7.) Replacement is the reverse. The magnet is useful to hold the bolt to the socket when trying to replace that poorly accessible bolt.

Estimated time required: 45-60 minutes