Thermostat Housing Leak, 01 S/T | Ford Explorer Forums - Serious Explorations

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Thermostat Housing Leak, 01 S/T


Well-Known Member
May 8, 2004
Reaction score
City, State
Millbrook, Illinois
Year, Model & Trim Level
2001 Explorer Sport Trac
I have been away from this forum for quite some time due to school and work, but I will need your guys help (which has always been great) with my mom's truck.

It is a 2001 Explorer Sport Trac, 4X4, 4.0L SOHC Automatic. 125000 miles on the clock.

I have been giving it regular fluid changes since we bought it at about 80000, and now we have a coolant leak. It is leaking at a seam on what I can only describe as the "lower thermostat housing."

I was wondering where I could get one of these, if it's a dealer only part, what is involved with replacing it. It looks like the upper intake has to come off as well for the housing to clear. This will not be a problem because I have been planning to replace the o-rings/gaskets on that manifold for a while.

I searched google and came up with another thread on THIS forum describing the part from Ford for the 2001 being a complete assembly at around $300. I also read about "modifying" the truck to a 2002 housing and changing the sensors accordingly.

Any help, info, advice would be greatly welcomed and appreciated.

Thanks much in advance!

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I have a 2001 sport trac , its the the o-ring or gasket is leaking at the base of unit, i've bought my therm. hous. at Bob Hurley ford online @delivered to the door for 238.98 total for the whole unit - yu3z-8a586-aa -.......good luck

Actually, mine is leaking at a seam about 1 1/2 inches below the thermostat. It seeps out all around that seam, which makes no sense!

I will talk to my mom and see if that particular part you mentioned she would want to order.

Also, did you have to remove the intake to get it out??

Yes, you`re right..there's a oring between the two halves about 10.00 for o-ring, but i otp for the whole unit ....not install yet,..waiting for my ford manual that i order off ebay this week,...some of the members say its fairly easy...i guess we'll both find out shortly...sorry i could'nt help no more than this....I'm learning as i go...good luck:)

Okay, so there IS another O ring... but it also looks like the piece is leaking at the bottom too where it meets (I THINK) the engine??

I think we will be best off replacing the assembly. I'm waiting for my mom to get the $ and a time where she can be without her truck for a few days.

I was in there pretty good looking around, and the two sensors come about 1/4" away from the bottom of the plastic intake. So i have a feeling the intake has to come off.


so i just pulled mine dont need to pull the intake manafold :) but now i need to find the part any websites?

mine came apart in the seam and i just orderd a whole new thermostat assembly.. i had less than 90k when mine went out.. my dad just changed his in his 04 at 72k..dealership said that they seem to go bad around 80-100k

Mine is leaking as well which i still need to get fixed. Just did the water pump. I've seen thermostat housings on ebay complete for around $120.

Anyone know where to find a good book that show "pictures" of how to get to the thermostat on a 2001 sport trac???