Thermostat replacement

[68Stang]

Check engine light came on and I received a message on my Ford Pass App - Service Engine Soon Warning "The engine control system has detected that the engine took to long to warm up to engine operating temperature. Lower Fuel economy may result"


After some research it appears my thermostat is stuck in the open position. I started the disassembly last night - air box and air intake tube. super simple and easy removal. With these out of the way it seems it will be pretty simple to remove the two bolts that hold the thermostat housing together and allow removal and replacement of the thermostat and thermostat O-ring seal. Containment of the coolant seems like the major hurdle.

Picked up the O-ring and thermostat from my local Ford dealer today.

I did a search here and didn't find much info on this process. Just interested if anyone has first-hand experience on this replacement.
Thanks - I always appreciate the group here as most everyone is helpful and I certainly welcome any words of wisdom.

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[Proshop]

Coolant containment as you stated is the hardest part of the whole install past maybe the oring not seating right. I just stuffed some towels down and they soaked up most of the coolant with out issue. Just make sure you replace what you lost and burp the system.

 

[tdstuart]

Ford service instructions are attached. Note the orientation of the thermostat.

For coolant containment take off the undertrays and covers. Put a large plastic container to catch the liquid and then put a cardboard box under that to catch any excess.

 

[SheepDog]

Remove your serpentine belt before you unbolt the thermostat housing. If you get coolant on the belt, there is a high likelyhood that it will chirp or squeek, and you will have to replace it.

 

[68Stang]

Thanks for the help and great info. My plan is to tackle this tonight. Hopefully I can report back in tomorrow with positive results.

 

[68Stang]

Unfortunately things didn't go as planned. The package had the correct part number but the thermostat inside was the wrong thermostat. Just picked up the correct one and plan to install tonight. I'll try to post an update once complete. The scary part is that the wrong part number thermostat fit but had a much smaller opening so it would have drastically restricted the coolant flow. I just double checked part numbers to be sure and realized it didn't match and then realized the opening was much smaller. Basically looked the same otherwise as most thermostats do. Lesson learned - open parts at the dealership and check the part number on the part.

 

[68Stang]

Correct thermostat installed, check engine code cleared, and everything back in working order.
The replacement thermostat is a little different design but it is the same size.
Here are the part numbers for the thermostat and the o-ring.

 

[Kachow]

Unfortunately things didn't go as planned. The package had the correct part number but the thermostat inside was the wrong thermostat. Just picked up the correct one and plan to install tonight. I'll try to post an update once complete. The scary part is that the wrong part number thermostat fit but had a much smaller opening so it would have drastically restricted the coolant flow. I just double checked part numbers to be sure and realized it didn't match and then realized the opening was much smaller. Basically looked the same otherwise as most thermostats do. Lesson learned - open parts at the dealership and check the part number on the part.

Your post is SO aptly timed. On Saturday my engine light came on, P0128! I noticed my car would NOT come up to temps. The Cylinder head temp wouldn't go above 170 when it normally hovers around 220.

I went to Ford and they ALSO GAVE ME THE WRONG FUCKING PART. They must have mislabeled across all dealers. I ended up going to Advance and got a Carquest thermostat. Works great, I'm glad I had a cup/container/microfibers as lots of coolant came out. The old thermostat was stuck open.

Now, I still have the check engine light on. I've only cycled it once. I don't have a code reader - will it clear after a set number of miles or drive cycles?

 

[68Stang]

This forum has been very helpful to me over the years so I felt like it was only right to try to document my issue so hopeful it would be helpful to others.

I tried the soft reset of the system and the code would not reset. I did drive it a little and it wouldn't reset. I just borrowed a friend's OBD2 scanner but I think you can take it to an auto parts store and they will clear the code for you.

 

[Kachow]

Advance and Oreillys wont do it, for legal reasons. Already tried with another car.

I'm going to keep driving it, and hopefully it will go away after x miles or x cycles.

If not, will find ODB2

 

[luca1290]

@68Stang How many miles do you have on the car? That engine bay looks like you live in world free of dust.
Congratulations on the level of upkeeping. I do keep my engine bays clean but this is another level...

 

[68Stang]

Not dust free here for sure but I do stay on the paved roads and also spend a few minutes after each wash wiping down the engine bay. It's probably not as clean as it appears in the photos. I do drive it!!
Thanks for the complement though

 

[galaxy]

@68Stang How many miles do you have on the car? That engine bay looks like you live in world free of dust.
Congratulations on the level of upkeeping. I do keep my engine bays clean but this is another level...

As someone that considers themself a pretty solid semi-pro detailer, I would tell you this car has one of the best sealed (in regards to dust) engine compartments I've ever owned. I've never had a car with an engine that stays as clean as the one in this thing. Which makes be beg the question when I see one totally destroyed..."how the f#$% did you even do that?" LOL!

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