1992 ranger 2.3 runs cool (coolant)

[twfmvm]

I had the thermostat replaced not long after i got it when i was getting other work done. The mechanic suggested it as it wasnt getting up to temp then. well now its cold out and the coolant temp gauge stays on "L" unless idling or in slow city traffic it will be slightly above the bottom of the normal range. ive put a piece of cardboard in front of the rad that covers up 3/4 of it. I've fixed the two check engine lights it had myself and the truck still gets 20mpg 70%city 30% hwy . Im thinking it could be the engine coolant temp sensor?

 

[Mark_88]

Do the heater hoses get hot? If they are not hot to the touch then the heater rad may be plugged...if you are concerned about heat in the cab.

If the hoses are hot to the touch then it might be something like the temp sensor is wonky...after a major overheat my temp sensor in the dash never did read correctly even though I was getting plenty of heat through the heater core and the engine wasn't running hot....this took a new rad and hoses to fix...not the heater core...

 

[RonD]

The engine computer and temp gauge don't share a coolant temp sensor.
Computer uses a TWO wire ECT(engine coolant temp) sensor
Temp gauge uses a ONE wire ECT sender.

Computer bases fuel mix on coolant temp and whether or not to run engine in Choke mode: rich mix, high idle and advanced spark timing, just like choke plate did on carb.

If ECT sensor is not increasing in temp after engine starts, or if ECT fails to reach 185degF after 10 minutes, the Computer will set a code telling driver of this issue, 21, 51, 61 are ECT codes.

Dash board temp gauge is easy to test, locate ECT SENDER, not sensor, it has only ONE wire.
Turn on the key, temp needle should move but just a bit.
Unplug the wire from the Sender, needle on gauge should drop lower.
Now Ground that wire, no it isn't a short, this is how the gauge works.
With that wire Grounded needle on gauge should go all the way to the top.

Some gauges will do the reverse of above, depends on the wiring.
So wire disconnected needle goes to top
Wire grounded needle bottoms out
As long as you get Full peg to peg movement the gauge and it's wire are OK.

If you don't get full swing of the needle then wire or gauge has a problem.

The ECT sensor or ECT sender just report coolant temp, computer has no control over engine temp, that is strictly a mechanical issue.


I guess first question is................is the engine actually running cold?
Is the heater only warm not hot?

If so then I wouldn't think BOTH the sensor and sender have failed at the same time.
The engine is running cold because of a mechanical issue.

Stock 2.3l thermostat is 192-195degF, some put in 180degF because of mistaken belief cooler is better, it isn't, it actually causes more engine wear and lower MPG.
190-210degF is best operating temp for engines made after approx. 1980

Test your Fan Clutch.
Start cold engine, you should hear fan noise when engine first starts and then that noise should lessen as the fan clutch disengages the fan blade from turning at engine speed, so fan is no longer pulling air thru rad, it is just spinning because of water pump motion.
After 30-60 seconds shut off engine
Try to spin fan, it should spin fairly easy, clutch is open and fan blade can spin.

The way the fan clutch works is that on its front side is what looks like a spring.
The spring is warmed up by the radiator, this heat from the radiator causes metal in spring to expand and this starts to close the clutch causing fan blade to grab more air cooling the rad more.
In cold weather fan clutch may never engage the fan blade, because rad never gets warm enough, this is normal in cold climates.

If your fan clutch never releases the fan blade then fan would be over cooling engine compartment, and this is it's "fail safe" mode, if clutch fails it is suppose to fail locked, because OVER cooling is better than OVER HEATING, lol.

So test it.

The cover in front of the rad is a good idea, it keeps the engine bay warmer, these are often added when you notice a coolant temp drop at highway speeds, because air flow thru rad is over cooling engine bay.
If temp drops more at stop lights then I would look more at the fan causing it, it is pulling air when it shouldn't.

2.3l doesn't produce alot of heat it is a fairly efficient engine in that respect, which is why it can run cooler than it should in cold climates.
Blocking rad is one step, insulating heater hoses is another, the flexible foam wrap for water pipes works fine for that and it is easy to add.

 

[Mark_88]

Ah, that's what was missing in my 88 Ranger...it had no computer but the temp gauge worked fine until the engine overheated...

It wasn't until several years later that I discovered, as usual by stumbling around in the dark one day looking for something else, that even though the temp sensor/sender was connected to the intake the way I'd had it for eight or nine years prior, the connectors were not a perfect match...the holes didn't line up with the wires...

How that worked I have no idea...maybe it didn't!

Anyway...I will be surprised if the OP comes back...not your answer, but the fact that they only have one post...that's usually why I send out a feeler question to see if they are serious or just someone looking to give negative rep...

 

[twfmvm]

Ill have to test the fan clutch. Id seen some suggestions elsewhere about that.. but i seem to get higher temps in stop and go driving. And times when ive been testing the truck at idle ive seen the thermostat 'appear' to kick on and decrease the temperature on the gauge. Ill get back on this once its done raining

Edit: Also it seems i get expected city milrage but my highway mileage is the same. Which to me suggests the increased air flow and cooling is causing the engine to run in choke mode and use extra fuel

Ill test the coolant temp sender as well

 

[RonD]

Also if you have the time, start cold engine and pop the hood, feel upper rad hose at radiator end, it will of course be cold.
Let engine idle for a few minutes and feel upper rad hose at radiator end again, it should still be cold.
If it is warming up with the engine then thermostat is not closed all the way, it is allowing coolant to flow into upper rad hose, so engine can't warm up.

If this is the case then you will need to change thermostat again or make sure it was seated correctly to seal engine system from rad system.
Radiator is only there to bleed extra heat from an engine, and some cold days it just isn't really used much.
The thermostat is there to set minimum engine temp, 195degF for the 2.3l, if coolant in engine only gets to 180degF then thermostat many never open.

Ford Temp gauge usually has 210degF as the center, so normal operating temp on gauge should be above 1/3 and below 1/2.

And contrary to popular thinking, using a 160degF or 180degF thermostat is not good for the engine nor will it delay overheating if cooling system has a problem.
Overheating is when coolant temp is above 240degF
At 240degF
160 t-stat is open all the way
180 t-stat is open all the way
195 t-stat is open all the way
lol, so t-stat temp wouldn't matter one bit, and no it doesn't take longer either, when 160 t-stat is at 195 deg it takes the same amount of time to get to 240deg as a 195deg t-stat would

 

[enjr44]

Well, I think if the engine is not getting warm there is something wrong with the thermostat or how it is installed or maybe the wrong one. The new "fail open" stats fail a lot more often than the old types did and they do fail open. Talk to a service tech and he/she will tell you they change a heck of a lot more of them than they used to. If the temp gauge goes up on a two mile long hill and drops coasting back down that hill the stat is not regulating the temp of the engine.

Cooling or heating the engine is all mechanical. If the coolant is not circulating out side of the engine it will get warm. The only place I ever saw engines stay cool was in Fairbanks in the middle of winter and they warmed up on the road.

My long gone 93 4cyl ran at just below half (like a couple of needle widths) at 40 below zero or 110 above. It never saw a garage and the heat in the cab got warm in just a few minutes (well, maybe a few more than just a few when it was really cold).

 

[twfmvm]

Im definitely thinking its the thermostat now. I checked the fan clutch too and it did not appear to release... it would turn easy but wouldn't spin freely. And the upper rad hose was warm after just a few minutes of idling. so where is the thermostat on the 92? Ive seen conflicting information..

Sent from my SAMSUNG-SM-G890A using Tapatalk

 

[mkyhmltn]

The thermostat on the 92 2.3 is on the head where the upper radiator hose goes in. Was having the same problem with mine. I ended up replacing the thermostat twice, still dont think its right. The ones I got from the parts store dont seem to fit /seal quite right so I think Im going to go to the dealer and get one there. Also replaced the heater core cause it was plugged and when I removed it to check it out and flush it it showed signs of a crack. Now it will warm up, just takes way longer than it should. Also ended up replacing the fan clutch as when I removed it it was missing bearings and wobbled all over the place.

 

[RonD]

If you can spin the fan after cold engine ran for at least 30 seconds it should be fine.
If it was locked you could try to spin it but it won't move after letting it go, if you can spin it and it does keep moving after letting it go it should be fine.

If does have a fluid inside so won't just spin freely even when unlocked.
Also when you first start a cold engine you will hear the fan, then after a few seconds noise will get less and less, that also means fan clutch is working, unlocking.

Make sure new Thermostat has a Jiggle Valve, yes that IS the technical term for it, lol.
Jiggle Valve is a small hole in the t-stat plate with a loose metal pin in it.
When installing the t-stat the Jiggle valve should be at the 12:00 position.
It is there to let air out when refilling the cooling system.
Hole is small enough so doesn't let enough coolant out to effect t-stat operation and engine temp, but large enough to allow air out so you don't get a "air block" in the system.

12:00 position is where the air would be
The Pin "jiggles" to keep hole open and free of debris...........Jiggle valve, lol.

 

[enjr44]

I also favor the OEM thermostats. But, they are sort of over priced. Make sure you get a new gasket.

http://www.fordparts.com/Commerce/C...d&mo=Ranger&cat=Cooling&catId=38365157#Search

 

[twfmvm]

So after checking a couple of times im sure the fan clutch doesn't spin freely (or as freely as i should think). After letting go it only spins halfway to a full rotation. Also even after a short drive the upper radiator hose gets almost too hot to touch. Especially after topping off the coolant. Should i go ahead and order a new fan clutch and thermostat/gasket?

 

[Mark_88]

I think you should burp the system and test the coolant temperature range. Make sure it is not going to freeze on you and worry about the fan in the spring. The T-stat with the jiggle valve actually helps keep the system free from air but it needs to belch properly when first filled...

Air in the cooling system can cause low heat in the cabin and poor circulation of the fluid...resulting in more complications and possible coolant expulsion...resulting in more heating/cooling issues until it looks like you are dealing with multiple issues...when in fact, you are still dealing with air in the system.

If you want to spend some money, invest in a rad flush kit and install that. This will allow you to fill the cooling system (and flush it in spring) and eliminate air pockets...and once that is done and the coolant mix is adjusted to prevent freezing...test it again...test the heat in the cabin....

 

[twfmvm]

By burp you mean taking the radiator cap off when cold and starting the engine and running coolant through the heater?

edit: and my heater seems to work fine, though it does take a few minutes to warm up.

 

[Mark_88]

yes, exactly...if you tried getting the air out by doing that it doesn't necessarily mean all the air is out...sometimes it takes a few tries...but it is better using the flush/fill kit on the heater hose...

I haven't tried this method myself...yet...but from what I've read it makes more sense...

My new engine is the 96 2.3 (actually a 2.5) and the upper rad hose is higher than the rad...I think mine still has air in it because the heater blows hot but also has cooler air than I expect...my old system always blew good and hot...most of the time

EDIT: Didn't see the edited part...if your heater works fine after the engine is warm then there is probably nothing wrong with it (now)...you may have corrected it by whatever you did...or covering the rad...

If on really cold days (-20 or lower) you find there is not enough heat...that may be normal too...there is a great deal of heat loss in these trucks and until you run around and stop up all the heat loss areas...like the space behind the jump seats on an extended cab...and the window space...not something I would recommend trying to insulate...lol...

Things like holes in the firewall allow cold air to enter the cab...as well as poorly insulated doors...although the 92 doors that I have on my truck now are way better than the 88 doors...and the carpet doesn't cover all the floor metal on a standard cab...there is a huge slab of cold exposed metal under the seat...and it radiates quite a bit of cold air...