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Discussion Starter #1 (Edited)
So I recently put in a new 180 degree thermostat while I had my intake manifold off to change the PCV and the manifold. After filling it up and bleeding fluid I'm noticing that my temps rise steadily after starting it cold but they never go back down below 210 degrees when I drive or when the fans kick on. So my car is constantly trying to cool down but it's not working. What direction should I head in? It's obviously a new thermostat and new coolant. I don't think my radiator is messed up but idk. Is it possible my temp sensor is being dumb? If it's my water pump how do I test it?

It's a 2.5 swap in a formerly 2.3 2004 Focus.

Update: SOLVED!
 

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... my car is constantly trying to cool down but it's not working...
No. Your engine is working normal. 210F is normal, that is not a hot engine.

With perfect cool/cold outside temperatures (40-50F), the engine cooling fans are not needed (never turn-on) and the engine operates in the 205 to 220F range. This perfect temperature range is controlled & keep in this range via the t-stat (opening & closing) and radiator coolant system ((no fans are needed)).

The engine cooling fans turn-on AFTER the temp gets even higher, at about 230F. At this temp, THIS IS WHEN the engine cooling fans turn-on at low speed.

Do not test the engine cooling system while the AC is On. The AC must be Off during these tests.

Edit: The temps above are what I witnessed on my car, which has a 180 or 185 T-stat installed. Test results can be seen at post#8 of thread linked below.
https://www.focusfanatics.com/forum/general-technical-chat/620497-2-3-thermostat-can-i-just-get-stat-itself.html
 

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A 180 stat does NOT hold the engine at 180 anyway, it is only guaranteed to be fully open then. Most stats will run the engine at 10-15 degrees hotter than the stat marked temperature and normal.

210 there is fine, it'll run forever like that.

The zetecs run at 210-220 using 190 stats...........
 

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Discussion Starter #4
So after further testing that thermostat was either the wrong temperature or defective. I got a different 180 thermostat installed it, bled it, tested it and now my car will get down to 190 when the fans kick in. Somehow the original "180" thermostat was a 208 as the car would refuse to dip below that no matter how fast you drove or if the fans were on. Further more when the temps would go higher they'd always shoot right back down to 210 once the fans were on but never below. That's a symptom of a wrong temp thermostat and I know this because my original thermostat would allow my car to get into the 190s and so does the replacement.

An important note I probably should have mentioned. This isn't a stock car, I have a tune that modifies the fan turn on temps and multiple mods including an engine swap. It's not stock nor is it supposed to run like stock. Thanks for all your help though!
 
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