Coolant temp gauge and fan issue

[My gfs explorer]

Two issues, possibly related, possibly not.

First. For years my girlfriends explorer has had a coolant temp gauge issue. See picture. Any input on what all it would entail to hopefully repair this cluster would be very appreciated. I have about average soldering skills.

Second. I noticed after installing a new water pump, that the radiator fan is seemingly on constantly on. No, the ac isn't on. But with all HVAC off and a cold engine, the fan came on immediately and never turned off for over half an hour.

A third thing, and I almost look at this one as good news everything else considered, I didn't change the thermostat when I did the water pump and I believe it is stuck open because during that half hour of letting it warm up, it would seem to lose heat during a long idle but would come back quickly when you pressed the gas. I'll have her hopefully verify that when she takes it to work tomorrow, but does that right? Also, upper hose never got hot or firm. Even though heat was blowing out of the vents.

For what it may be worth, 04 Explorer, 4.0, 4wd, flex fuel.

Thanks in advance for any input or advice.

 

[My gfs explorer]

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[TechGuru]

as for the cluster I'm pretty sure the needle just slipped on the shaft and could probably be fixed by removing, adding a dot of super glue then putting it back in the correct zero position.

Fan constantly on? Yours has a electric fan? My 03 only has a clutch fan so I have no experience to help you there.

Always replace the thermostat when replacing the water pump. It definitely sounds open. I would only use a Motorcraft thermostat.

$28.99 https://www.oreillyauto.com/detail/c/motorcraft/motorcraft-190-degree-thermostat/mot0/rt1167

$16.62 More Information for MOTORCRAFT RT1167

Also while changing it I would upgrade to a metal water outlet/thermostat housing.

Two-Sensor Metal Housing: More Information for SKP SKRH144D

One-Sensor Metal Housing: More Information for SKP SK121259

 

[My gfs explorer]

Ok. So with your help, thank you b the way, I finally got enough info to report back. Here are my findings.

First, the instrument cluster. Took it apart. Reset it. The needle was NOT stripped or loose. I could feel it was connected to whatever turns it. So I just rotated it back to zero and put it all back together. Started the car, seemed to rise as intended. But when I shut the car back off, instead of resetting back, it kinda twitched and rose further. I repeated this but just cycling the key to on a few times. Kept rising, past HOT. I tried to get a video of it doing it but didn't have much luck so here is a picture of where it is now. Any further advice?

Second the fan. Yes it's a clutch. I even knew that having just taken it off for the water pump. Forgive me, it was a really late night. I do however still think it is staying engaged though. It's loud, at idle, even with a cold engine. And with the engine off trying to freespin it, I get about an half turn out of it. That about right or no?

Third, thermostat and housing replaced. I'm actually thinking it was leaking out of the coolant temp sensor port now because of a flattened o-ring. And per another thread on here, picked up some o-rings from home depot, replaced it, and so far so good.

Thanks again for your help.

 

[TechGuru]

Ok. So with your help, thank you b the way, I finally got enough info to report back. Here are my findings.

First, the instrument cluster. Took it apart. Reset it. The needle was NOT stripped or loose. I could feel it was connected to whatever turns it. So I just rotated it back to zero and put it all back together. Started the car, seemed to rise as intended. But when I shut the car back off, instead of resetting back, it kinda twitched and rose further. I repeated this but just cycling the key to on a few times. Kept rising, past HOT. I tried to get a video of it doing it but didn't have much luck so here is a picture of where it is now. Any further advice?

Second the fan. Yes it's a clutch. I even knew that having just taken it off for the water pump. Forgive me, it was a really late night. I do however still think it is staying engaged though. It's loud, at idle, even with a cold engine. And with the engine off trying to freespin it, I get about an half turn out of it. That about right or no?

Third, thermostat and housing replaced. I'm actually thinking it was leaking out of the coolant temp sensor port now because of a flattened o-ring. And per another thread on here, picked up some o-rings from home depot, replaced it, and so far so good.

Thanks again for your help.

I think your IC has this problem



You either have to replace the servo or the entire thing.

A good fan clutch will enguage when cold. Hold it at 2500 RPM and you should hear the roar of wind subside after 30-60 seconds.