I have a 95 Ranger 4.0L s/c 4x4. I had problems about 5 years ago, whereby the dealer replaced the sending unit for the temperature gauge (it was under factory warranty at the time).

Now I noticed that the temp gauge hardly reads at all, just barely goes into the "normal" range. There is no change in the performance of the heater, as it seems to get up into operating temperature as quick as it always did, and there is no change in the engine idle speed, that may be seen if the stat was stuck open and the computer was trying to get the engine up to operating temperature.

I checked the sending unit with a ohm meter and it is definately not to the specs listed in my Haynes manual.

My question is, has anyone else had these re-occurring problems with this part, or is it something that just gets replaced every 5 years?

Not a biggie, only a $10 part and easy to install, but this will be the 3rd one on my truck.....just wonderin'

 

I have a 95 4.0L, 2wd, supercooling I believe - have replaced the sending unit three times (that I can remember because of a fluctuating gauge). Whenever I change coolant, I change the sending unit as well - just got used to it.

 

Forgot to add - I eventually bought a OBD-II reader that also does temp, speed, etc. When the temp gauge strated acting funny again, I hooked it up and drove around - seems that the gauge is pretty sensitive, large changes arent a huge change in temp once the gauge registers, but it also did show that the coolant temp was what it was supposed to be, sending unit was bad.

 

jmq
I have been looking for a code reader for about a year for my 95 Ranger with no luck. Can you tell me the brand and model of the one you have? Thanks

 

My truck is OBD-II, for some reason some rangers (not sure if all) were OBD-II in 1995. Anyway, I bought a connector from obd-2.com (no connections, etc.), guy named Alex Peper - hooks to a laptop, software free. Software is updated very often, works for me, and you get realtime scanning (temp, rpm, o2 sensors, etc.).

 

94 XLT s-cab 4.0L 4x4, original owner.........I've been through five so far and it's time to make it number six. I too replace them every coolant change, that is, if they last that long. They eventually wind up producing low or erratic and wandering temp gage readings.

 

Thanks for the replies, sounds like another engineered to fail part by Ford. Got the part and will change it this afternoon. Whoever was looking for an OBD2 code reader, I just bought one, and Eqqus model 3100. Cost around $200 (in Canada) but has already paid for itself twice over between me and my friends Mazda. Best tool I ever bought.

 

***UPDATE***
I replaced the sending unit, and to my dismay, there is NO change. I ran the truck at idle for about 20 min after and the gauge hardly moved. I noticed that the recovery tank was quite full and the coolant inside was cold. The top rad hose is hot indicating that the coolant is circulating.

I can't really figure this out. I would think that if the thermostat was stuck open I would never get any heat inside the cab. I do get heat, fairly quickly, I don't know how hot it's supposed to be, mind you, but I'm comfortable.

The last time this happened, I noticed there were problems because the engine was idling high. Truck was under factory warranty at the time, the dealer said the computer was sensing this and raising the idle to try and bring the truck up to temp. I'm not getting any of those symptoms this time.

My question to you guys is, can the thermostat be stuck open just enough to give the cab a decent amount of heat, but at the same time not get the engine up to temp?? Any why is my computer not raising the idle to compensate??

At least these parts are cheap, $10 for sending unit, $12 for thermostat.....Any thoughts???

 

When I replace t-stats, I look at the round brass portion that slides back and forth around a round shaft. Every time I've replaced one, there seems to be abrasion between these two and I've always wondered if there is enough friction to cause the slide to hang up for awhile until the engine overheats slightly, thus dislodging the slide. I've put t-stats in a pan of water on the stove and put a thermometer in the pan and turned on the heat in an effort to prove this, but so far I can't prove it. Not really sure what to say. I kinda think this issue is just the nature of these engines.

 

***LAST UPDATE***

Just got through changing the thermostat. I guess it was sticking open because now I have HEAT when I pu the heat on in the cab. I had warm air previously, now it's hot! Almost too hot to hold your hand there for too long. I examined the old thermostat but I couldn't see evidence of any abrasion or friction marks that would have made it stick. My gauge now reads near the middle of the normal range.
Everything seems to be working well now. Well see.....