backinblack68

Had the same issue-pep boys would have charged about $350 on a friday night when no other shops are open. They actually showed me a diagram on their computer of what needed fixing, so I decided to fix it myself. Thought it would be an easy thermostat replacement, but these mustangs have a cheap Plastic housing that swells and splits at the seam that I think was only glued? together! Only place in my town that had the part was the ford dealer. costs about $90. got the thermostat at pep boys for about $20, took the broken one off, and the new one on, but it still leaked immediately! found the old O ring on the bottom of the busted housing, and reinstalled the new thermo and housing with this o ring gasket and it worked perfect! total cost was still over $100. found out later you can buy a metal heavy duty housing-might consider this soon!

Nice Pony

Where can you find a metal housing? Been looking for 2 years and nothing!!!

tx_zstang

I bought thermostat and o-ring at AdvanceAutoParts, but most any place will sell them.
The t-stat simply rests in the bottom part of the housing.
The housing itself is where we have problems.

amustangrocks

its a real common problem with the 4.0`s. heres a write up i did on another forum on replacing it.
http://www.allfordmustangs.com/forum...-how-pics.html

Blue_steel

reviving this thread...I can't seem to get the sending unit to fit in the new housing properly with the clip.I am trying some rtv to get it to seal i will update tomorrow.

Nice Pony

Go to a hardware store and find a new O-Ring that is slightly thicker so it fits tighter. I did this and it worked just fine. Lube it up real good with a little oil or grease and it should slide right in.

amustangrocks

if you cant get a oring that makes it work, just buy the new sensor and it will fit right in the new housing. dont rely on that junk sealant.

SoFL05GT

The same happened to my son's 2006 V6 pictured below. I was changing the oil when I noticed some coolant dripping down. It was a small leak and I could tell it was coming from the thermostat housing area. The car had about 63,000 miles on it and we had Ford's ESP. However, the ESP was only good for 60K, still Ford Customer Service came through and paid for the repair. I know they replaced the housing, thermostat and some small hose. I can look up the repair order and see exactly what parts were installed, if it helps.

Blue_steel

I tried a new ring and could not get it to work.So if I get a new sensor it should fit better than the old one in the new housing?

coreyhudson@gmail.com

[QUOTE=Nice Pony;7415487] Just go to your local hardware store and find a O-ring to replace the stock one since Ford does not sell that by itself.

I've run into this problem on my '07 as well. I'm doing the job myself, and I had a heck of a time finding the parts. However I could not find this o-ring. I'd love to do as you suggested, but I have no idea what size to get. Do you know the measurements for this particular part? I ask, because once my car is disassembled, i will have no way to get to a hardware store, so I would like to get the o-ring before I begin work.

Any info helps. Thank you.