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?

 

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.

 

Does the water pump have a weep hole? If so, the coolant may be slowly dripping out of that, but only when you are driving. That would explain why you're not seeing a puddle build up when it's parked.

 

Thanx for the link, works great.

Weep hole...that seems to explain that. What's the purpose of the weep hole? Is this monthly coolant loss by design and the expectation is to periodically add coolant? Where is the weep hole because I can't seem to find it? If there's a weep hole should I replace the water pump with one that's sans weep hole, or the hole should be there?

 

It's designed to allow excess lubricant out of the pump itself. But if the internal seal(s) is(are) comprised, coolant can seep past it(them) and slowly leak out through it.

 

Ok, this is making sense now. Just read a good article on this here. I will get under the truck as I am about to do oil change. Looks like I might have me a water pump job. The belt is in need of changing anyway.

 

Drive the truck and let the engine get to operating temperature. When you stop and shut it off get down under the front end and look for a fresh drip. If it happens to hit something before the ground, it may not be enough coolant to drop further down and hit your driveway.

 

Before driving off I checked and found a leak on the driveway after the truck sat from 8pm Saturday and all day today.
I drove around, came back and I just couldn't see any leaks from under. It's been 2 hours and there's still no leak on the driveway-will see tomorrow AM.

The only thing I noticed was the temp dial would fluctuate gently up and down between the two points in pic below. It didn't hold steady once it got up to level in pic 1, it didn't matter if I was cruising at 40m, slowing down, stopped, gaining speed... it would gently rise then at some point fall slowly, wait then rise gently. There was no determinable method..

Also temp dial just doesn't get to a hair below half which is where I remember it being normally, because about 2ish years ago I had posted on the forum, I forget but about something that required temp gauge observation, might have been a coolant flush.

 

Acts like a ThermoStat StuckOpen or with wrong TempRating.

 

Wrong temp rating would be caused by heat sensor and sending unit? I read here about someone replacing those as they were corroded & gunked up and that fixed their issue. I found my coolant reservoir empty and rad's level was just above the fins. Does this sound like I have a different problem or start with replacing the heat sensor & sending unit? And if necessary next the tstat before water pump, if so?

 

I'd start with the easiest\cheapest possibilities; install a new ThermoStat & RadiatorCap.
Test drive a few times, before considering other more expensive items.

 

Sounds good.
First, On that post I seen mentions preferring 195 degree Tstat. Is this something I should consider? The ones I see at AZ, O'R are 192 degree.

Secondly, Are these ok?
1-Duralast Thermostat 30692 or
2-Murray Plus 192 Degree Thermostat
3-Failsafe Thermostat 7306-192

 

My preference would be a 192f FordMotorCraft or Stant brand ThermoStat.
Stay away from "FailSafe" thermostats; if that's currently in your engine, it may be causing your problem;
they intentionally latch\lock full open when overheated; not good.
Also check small hose from the RadiatorCap to OverFlowTank for leaks, replace as needed.