2002 F150 4x4 SuperCrew 5.4L

A few years ago she stuck open, so I replaced it with 'whatever the guy at napa gave me when I gave him the vehicle info'. It hasn't given any problems, but on a 95 degree day, idling, the temp will hang out around 198-205....Ive seen it at 208 according to my ScanGauge that's reading from the port. It hasnt really concerned me but I don't remember having my fan run as much as it does before the original t-stat crapped out. I think it comes on at 204 ish.

Then again, 200-205 according to research is on the mark. So, I was thinking of putting in an OEM one because i don't have anything else to fix right now. But my search of Rock Auto gives:

RT1234, RT1144 (pretty sure this is for the Lightning), and then the Ford Parts Search Engine yielded RT1118. LOL.

So, Im not sure what its SUPPOSED to have and I wasnt smart enough to look when I replaced it a few years ago.

Thanks in advance.

1118 is what you need.

the 1144 is for the DOHC.

That reminds me to ask you guys (and girls) a question about my most recent thermostat replacement.

My 2001 Ford Sport Trac has about 250,000 miles on it.

I repalced the tstat housing and the water pump. After replacing the tstat, it seems like my truck doesn't get to the mid point of the coolant temp until much later now...perhaps 4-5 minutes more of driving, and that is even on a warm day.

I think the part number was RT1167 from Motorcraft, and it is listed at 190F. My only guesses are this:

1) The thermostat is a higher temp than my previous (perhaps the OEM was 170/180?) and it is opening later.

2) Water is bypassing the thermostat for whatever reason (user install issue?) and the coolant is getting cooled more.

I suppose I could check to see if coolant is being dumped back in the tank as the engine is running. Any other suggestions?

If it takes LONGER to get to op temp, I would suspect the thermostat is a LOWER temperature than the one that was on it before. Since it opens sooner, the guage reads cooler longer. I guess you could have a fan clutch that is always engaged somehow, but I dont know how that vehicle works.

When I had thermostat problems on this truck, it was the t-stat that was stuck OPEN. So, on a cold day, it would take a LOOOONNNNGGGGGG time for it to get up to operating temperature.