hmmm i did this several months ago...
yeah i think you do have to twist the t-stat in now that i think about it... i'll review a little bit & see...

i know there are tiny differences in the 98/99 2.5 & the 00/01 2.5, maybe the t-stat is different as well...
.........
i see the slot that the tabs slide into when inserting the t-stat... i was a bit hasty with the pics cause i was in a hurry, but if it required twisting, then i'm sure i twisted it in. it's hard to miss if you should, cause you'd be able to see the lateral grooves that the tabs seat in...

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1999 xlt 2.5l 5-speed Supercab 159k
83 diesel 2.2l na
06 F250 6.0l psd
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