Is Temp. Too Low? And Tranny Fluid Change

[Jay11]

1998 Ranger 2.5, 86k
Noticed that after 30 minutes of driving temp gauge is at level in pic, falls a hair or two just below that at a stop light. Temp outside is 80F. Coolant level is aok but I do add a little bit after say 2 months. Never been able to figure out why the loss occurs. Trany fluid and engine oil are aok, not frothy or coolant contaminated. Can't think of anything else regarding that. Is this an indication of a concern or am I just splitting hairs?

Second Q? I would like to assume tranny fluid was never changed before I acquired the truck or if lucky may be at 30k miles but I am not counting on that. In which case I think I should drain so much quarts and refill, and repeat at plus 30k. I certainly don't want to take it in for a flush or full drain. I am thinking a partial change would be preferable at this mileage. What do you guys think?

 

[DILLARD000]

Get yourself an OBD2 scanner that reads+displays data while driving; click here for info on the scanners I use.
Cluster gage is not precise\accurate; it tells you if engine is cold, warmed up, or overheating, but not much else.

If Tranny Filter has never been changed, probably should do so.
I hand pump ~1qt of old ATF & refresh at the Tranny DipStickTube every 6months with Engine Oil+Filter changes;
then do Pan drop, Filter change & 5~7qt ATF refresh every 33k Miles, roughly every 4~5years with current driving habits.
Don't do any commercial shop Tranny flush or cleaning.

 

[Jay11]

Get yourself an OBD2 scanner that reads+displays data while driving; click here for info on the scanners I use.
Don't do any commercial shop Tranny flush or cleaning.

Link to scanners is not working. What's the model, I can search for it and compare with Autel All Systems Scanner or this one here. I've been delaying buying a good scanner and I think it's time. So any link to comp would be great before I decide on which one.

And definitely not doing commercial flush.

 

[Jay11]

If Tranny Filter has never been changed, probably should do so.
I hand pump ~1qt of old ATF & refresh at the Tranny DipStickTube every 6months with Engine Oil+Filter changes;
then do Pan drop, Filter change & 5~7qt ATF refresh every 33k Miles, roughly every 4~5years with current driving habits.
Don't do any commercial shop Tranny flush or cleaning.

Found this thread here, seems similar to my situation. Something about Tstat failing. How can you tell or diagnose a Tstat issue?

 

[DILLARD000]

Huh, link works for me from here both on AndroidPhon browser & on PC browser?
https://2001fordexplorersporttrac.fandom.com/Electrical_OnBoardDiagnosisPort
Anyway, I've got the OBDLink# MX+ that works via BlueTooth to my AndroidPhone
& the OBDLink# EX that works via USBCable to my WindowsLapTop; google those models.
These work for me; certainly there are cheaper\lesser & much more expensive options for ODB2 scanners.

Yep, ThermoStats typically, not always, fail in the open position.
For example., during a previous drive, engine was fully warmed up & ThermoStat was full open, meaning full flow thru radiator.
And during that previous drive the ThermoStat became mechanically stuck in the full open position.
So instead of closing the radiator loop after that drive as the engine cooled down, it stayed open.
So during your next cold morning start, the engine starts cold with full flow thru radiator,
& it never fully warms up to ~190f normal operating temp, but stays cold & you don't get adequate cab heat either.
Above is a common scenario\result of a ThermoStat that has failed open.
Living in a hot climate like TX, you may never notice the stuck thermostat, because you never need cab heat,
but MPGs will suffer because engine controls never go into closed loop & fuel/air ratio runs rich.