Hey all !!!
Before I get in deep.. I do have an aftermarket napa t Stat in there now...not sure what was in there. ..saved it..
What do I look for to confirm its an oem or aftermarket. ..what's the difference?
Either way it behaved the same with both thermostats.
I have been reading and it seems pretty clear I need oem...but just trying to understand why? Something to do with a by pass in the block instead of the thermostat itself..
Symptoms are low heat, temp guage barely moves except longer highway trips/ but more so in the summer with the AC on... and its not by much. ..get off the highway and it cools right down...
Also I see you can supposedly get oem ford t stats from Amazon. .. wonder if it's legit?
Just trying to learn something new in the process here
Thanks gang
Happy New Year

 

happy new year brother.here's the info your looking for:
Reason why it's IMPORTANT to use only FORD/NAVISTAR Thermostat's in these engines!

 

I've never had any trouble with aftermarket ones; I've actually got a real temp gauge and found that it opened and shut quite consistently around the 190deg mark(which is what it said on the package).
My truck's never had any trouble warming up(at least, as long as you actually do something other than idle it at no-load), and has never overheated on me once I installed my new thermostat(the old one eventually stuck shut; it'd stay under 212, barely, without a load).

 

My understanding is that some aftermarket thermostats just don't allow enough coolant to flow because the aperture doesn't open as much, but I have no first-hand experience.

As for ordering on Amazon, it's legit. I order nearly all my auto parts from the now. Use some other site to validate tour part numbers, though. Rockauto.com is a good one else to use for that.

Mike

 

The aftermarket ones don't have the by-pass block off like the OEM one does. It actually lets too much coolant pass through it, so the block never warms up like it's supposed to, and cools off way too quickly. The OEM ones are more of a two-stage thermostat. The aftermarket ones are one-stage. If you have an OEM one and an aftermarket one side by side, it's really obvious what the differences are.

 

The Chinese ones break:

 

I ordered a motorcraft one off Amazon, its legit.
Works fine too.

 

Thanks for all the replies gang and for steering me to the link..
I did find the old one...can't tell by looking at it, yet??
Gonna order it up from Amazon with out trying anything else and see what happens...
Before I got to the heat problem I had just assumed the gauge was screwy. But it did move when I grounded it ...
We shall soon find out.... just fixed the blower motor and
resistor..... Bring on the heat!!!!!!
Thanks! !!!

 

You're using the stock gauge in the dash, right? If so, that's most likely your only problem.
Get an infrared non-contact thermometer and check out your hose, head and block temps once hot, should see normal temps and can gain some peace of mind. Or install a real temp gauge, I did that too and for the most part my temps are rock stable.

The factory gauge is total crap and cannot be relied upon for anything. I love this era Ford Diesel but hate what Ford did with the dash setup. Dummy oil and temp gauges, REALLY?? Come on...

-Joshua

 

iv got the grill cover on chip truck now.makes a big difference in heat in the cab even with the temp gauge reading 192F warms up a lot quicker and the heater blows higher temps.with a t-sat i dunno if i really understand it but it's not a placebo.they work.

 

f250 - what kind of grille cover do you have? I use a cardboard box and it serves it's purpose well but needs to be replaced after a good rain/snow.

 

it's a fia WF922-2.
here it was on log truck temporarily (for some reason.i don't remember why i had it on that truck.it's chips old grill,but i dunno why i clipped on the cover.must of wanted to bring it up to temp quicker......hmm.checking timing or testing fan clutch or something.i dunno lol.that was last winter.)

 

Awesome. Thank you. I noticed a big difference in heat output and it seemed to run smoother with the grille covered the few times I did it. I know my t-stat is correct, water temp gauge is 'in the ballpark,' and the fan clutch is working as it should. Thanks again.

 

I like the idea of the infrared thermometer.. Could use on many things...
can you make any recommendations? do the cheap ones work well, or do I have to drop some coin?
As far as gauge and actual temp, I can say this, I can grab my upper hose and heater hoses...barely above luke warm..
Real gauges are probably a good idea as well
Thanks

 

your t-stat is stuck open for sure if your upper hose never gets warm but the truck doesn't overheat.