which thermostat to buy?

[dean71]

First, i would like to say thank you for all who have contributed to the threads which helped me diagnose and repair my LS overheating problem.
i have a 2001 3.0 automatic with 124000 mi
had an overheating problem.
replaced degas bottle, all plastic coolant hoses, thermostat, hydraulic actuator solenoid. bled the system....bled the system...oh, and bled the system
i repaired it last summer. over this past winter, i noticed the fan running at high speed. I understand it will do this when the AC is on or when it is in defrost. but, it does it when the AC is off. The car is running at (what seems to be) normal temp. the gauge is right where it was when i originally purchased the car which is just below the middle.
so, i have searched and read tons of threads on fan running at high speed(some of which do not have an answer). I bled the system again.. i get a steady stream of coolant with no bubbles. I am leaning more towards having the incorrect thermostat. I do not have the original package and i do not remember which one i purchased (O'reilly outo parts).
There are several tstats to choose from:192, 188 and 180..Is it possible i installed a 192* and this is causing the head temp sensor to tell the pcm to kick the fan into high?. i just need to know what Tstat to buy. I dont have any ford diagnostic tools to read all the sensors at operating temp and the ford/lincoln dealer wants me to leave it overnight. i need the car for work, so thats out. any ideas? I live in California where the summer temps are between 95 to 110. Thank you in advance for the help

 

[oddball]

I did have problems with a new thermostat and switched back to the original. I think the actual problem was just a big bubble that wouldn't flow out, and re-opening the system to replace the thermostat seemed to fix it.
I think 188 is the stock temp.

When it's on "high", go ahead and turn on the A/C and see if it goes to "higher".

 

[dean71]

i will bleed the system again, but i am more than sure all the air is out...It makes no difference if the ac is on or off..as soon as the car gets to operating temperature, the fan goes to high. I will pick up a 188* tstat..is it worth getting directly from the dealer, or are the parts stores aftermarket just as good?

 

[joegr]

i will bleed the system again, but i am more than sure all the air is out...It makes no difference if the ac is on or off..as soon as the car gets to operating temperature, the fan goes to high. I will pick up a 188* tstat..is it worth getting directly from the dealer, or are the parts stores aftermarket just as good?

192 is the correct thermostat temperature (but 188 is close enough). The fan doesn't go to maximum till it gets considerably higher than that. Have you attached a scan tool with live sensor readout to find out what is really going on? I would do that and use a thermometer to compare what the PCM thinks the temperature is to what it really is.

 

[T-Money]

If the gen II thermostat is the same at the gen I then i have a used gen II thermostat for sale. Car had 46k when it was removed.

 

[joegr]

If the gen II thermostat is the same at the gen I then i have a used gen II thermostat for sale. Car had 46k when it was removed.

Not the same.

 

[dean71]

192 is the correct thermostat temperature (but 188 is close enough). The fan doesn't go to maximum till it gets considerably higher than that. Have you attached a scan tool with live sensor readout to find out what is really going on? I would do that and use a thermometer to compare what the PCM thinks the temperature is to what it really is.

ok..my scanner does not have Live Data functionality (innova 3100). i will find a better scan tool and try that.

side note: i did notice over the winter when i reset the pcm, the fan didnt return to its high output for a day or two

If the gen II thermostat is the same at the gen I then i have a used gen II thermostat for sale. Car had 46k when it was removed.

Thanks for the offer, but i am sure i can find a new replacement here in town.

 

[dean71]

i bled the system several times over the last couple of days hoping to find air in the system..nothing...still running on high speed. today i picked up two thermostats (192 and 180). i installed the 192* with no change.
i installed the 180* which did the trick. i can barely hear the fan running. I drove around with the AC off for 45 min. fan is still pulling air. temp is holding steady just below the half mark. i turned the AC on and the fan kicked up high, but not as high as it has been running..i am happy .
The car is due smog check next year, so if the car running a bit cooler causes it to fail emissions, i will throw the 192 back in and then change it back out after it passes. i still need to purchase a live data scanner to see if the rest of the sensors are reading correctly. Thanks again to everyone for the help.