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Discussion Starter #1
I'm hoping that with other forum member's participation we
can better determine what our stock temp gauges are telling us.
Further learn how to troubleshoot the circuit more precisely as well.

I see many members saying "my gauge points to the "A" in "NORMAL"
is that bad?", or something similar.

Right out of the gate let's acknowledge the temp gauges in our
Escorts are crap. That out of the way please no suggestions to
replace the gauges. These are the gauges we were dealt let's
work with them.

Three things determine the reading on your temp gauges:
1. Accuracy of the Gauge
2. Accuracy of the Coolant Temperature Sending Unit
3. Actual Coolant temperature

All of us with the 1.9L 2nd gen has the Heater Core inlet pipe
with two or three Sensors threaded in it. The one with the right
angle connector is the one we'll be dealing with here. The Pipe
is grounded through a bracket and that can effect the Accuracy of your
Gauge. It needs to be connected to ground, the closer to ground the
better, because the case of the Sensor also needs to connect to
the Pipe. Don't make the mistake of insulating this Sensor from the
pipe with a heavy amount of Teflon tape. I re-threaded mine with
Permatex Ultra Copper High Temp Silicone (red) near the back of
the threads and then rechecked for a good connection to the Pipe.
Before doing this I cleaned the Pipe threads with a spark plug wire
brush and vac'd out the debris with a shop vac attachment.

Here's a pic of the sensor used for the Gauge before I re-threaded:



The Sensor or Sender is basically a big Resistor to ground (thus the Bracket).
This is why the Sensor only needs one wire to connect to the gauge
and complete the circuit.

For the other's sensor's go here:
http://www.feoa.net/modules.php?name=Forums&file=viewtopic&t=60690

I wanted to know what resistance value was required to deflect the gauge.
Haynes said 74 ohms to "C" and 9.7 Ohms to get it to deflect to "H" hot.
So off to Radio Shack to get these values. STAY WITH ME YOU CAN DO
THIS TOO. While I was there I decided to get a few more values in between
for grins and giggles. I spend about five bucks to get them. They're
big "bathtub" 10 watt resistors. You can get smaller physical sizes
(wattage) but I found these easier to work with.

Here' s what I got, each had two per pack, (2) 10 ohms, (2) 50 ohms, and (2) 100 ohms
resistors :



I made two Resistor configurations to provide my Values for Testing:



You don't even need a knowledge of ohms law to do this. Just arrange
the resistors like I did and you'll get my test values. Two 10 ohm resistors in series
as shown will give you a 10 Ohm value between points "A" and "B" and a
20 ohm value between point "A" and "C". It's easy. Then take the remaining ones
and twist together the two 100 ohm values and also twist together the two 50 ohm
values and then simply connect them in series as shown. Now you've got 25 ohms
between points "D" and "E", 50 ohms between points "E" and "F" and 75 ohms
between "D" and "F".

With the Key off, pull the Connector off the Sensor and connect it to
point "F" the 75 ohm value and connect "D" to battery ground or the bracket
if you want to test the bracket too:



Make sure you have some of these alligator clips to make it easy:



Then simply Turn on the ignition without starting and you'll see your
Gauge go all the way to COLD. Put in the 10 ohm and It'll go all the way
to HOT.

I then proceeded to substitute all my remaining values for my 1991 and 1994 and
plotted the results for you on a Pic of my Gauge using MS Paint:



I didn't show the 10 ohm and 75 ohm deflection for simplicity's sake.

So where does your gauge normally run at?

My 1991 Pony Automatic is running in the middle on a 75 to 80f day,
which correlates to 25 ohms. And my 1994 Pony 5 speed runs just a bit
over it's 50 ohm mark under the same condition.

I may still have a problem with running hot on my 1991 I'm still investigating.
Notice the 1991 gauge is a little forward on all the values. So even if I had the
exact same Sensor in both, the 1991 would still be a tad forward on the Gauge.

Next I'll check the Resistance of the Sensor itself at various temps. My 91 uses
an aftermarket Temp Sensor and the 94 is still a stock sensor.

Comments Please!! Where does your temp gauge show? Did this
help with your troubleshoot? How? All comments welcome that's how we
figure this stuff out.
 

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I'm glad you stated this thread, I asked the same question a few weeks ago and never got an answer. I have had two Escort LX 1.9s, a 93 that we had a little less than a year (totaled in the rear by an idiot in an F150, at a stop light) and its near identical replacement 94, still running great 15 years later at 172K.

Both cars coolant temps ran (or currently run) normally between the N and O of normal. If I have the AC off, the temperature controlled fans won't come on until the gauge runs way up to between A and L or so, and the car appears to be running quite hot at that point, if the car is idling or in slow moving traffic. While moving at anything above a bumper to bumper crawl without fan assist on the radiator cooling, it will be stable at the lower reading.

If I see the temp creeping up while idling or in traffic, I will go either to defrost or AC which kicks the radiator's fans on full time. This will return and maintain the temp at the N and O, which appears to be the set point of the thermostat. I use 190 degree fail safe (fail open) stats. On at least two occasions, the stats have failed open on a temp excursion to the upper end of the "NORMAL" temp indication range when the car was allowed to idle for extended periods. After the stats fail open, especially in the winter, its' tough to get the temps to get much up off the bottom peg of the gauge, although they will eventually go high in idle or in traffic without AC or Defrost.

Again, I believe this is "as designed" performance, as both the 93 and 94 worked the same way right from the dealer.

I also am curious how others' cars perform. In contrast, my Volvo ( and several other 70 series Volvos I know of maintain a rock steady temp indication regardless of AC status. The Escorts appear unique in having the big temp excursions wit the AC off.


Chris, Stonington, CT

94 Escort LX 1.9 5 Speed 172K
98 Volvo V70XC 162K
 

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Discussion Starter #3
Here is the Chart of Temperature Vs. Resistance of 3 after market
Coolant Temperature Sender Units.



Units A and B are Sensors (BWD# WT386Z) I just bought today at
Advance for $3.99 each. They are made by Standard Motor Parts
(BWD) I believe.

My thermostat is calibrated to open at 195F. Using the chart I can see
that my old sender was reading 29 ohms at 195F, that means that the
initial warming point where the Thermostat Opened would coorelate
with a reading of on my 1991 Gauge of just under Half deflection or "O"
on the gauge. A reading of 25ohms would put me right in the center
at "R".

Interestingly when I drove out for Lunch on Friday I measured the
the temperature of the Thermostat housing /head interface right at
200F using a Infared temperature reading and the gauge was nearly
in the center.

So, If I replace my old sensor with unit B from the chart, and given
the calibration of my 1991 Temp Gauge, it'll read just under center point
when the Coolant reaches 210F (28 ohms). I understand that the cooling
fan doesn't kick on until the PCM sees about 215 to 220F or .55V to .45V
at pin 7 (blue/white wire) at the PCM connector as reported by the other
Sensor the ECT (Engine Coolant Temperature) Sensor. Therefore doing a
bit of extrapolation I would guess that unit B will be at 26 to 24 ohms (215
to 220F?) before my fan would kick on. A bit over the Gauge center point
and the radiator cooling fan should come on.

I'm missing the resistance readings (ohms) for 215 and 220 because the
wife didn't want antifreeze cooking in the kitchen so I used water for my
testing. ;)
 

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My current 93 runs exactly where your 94 is running (stock sensor).

Very helpful I think as it will solve the "where should my gauge run" question.

Job well done!
 

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hey guys kinda errelivent as far as i personally think but my gauge con cold starts sits below the C bout half inch and when at normal opperation temperature it site between N and O or normal
 

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Discussion Starter #6
racethisescort89- I've found that the Temp Gauge for my 95LX Escort Wagon 1.9L Automatic is different. In fact, the Sender although it looks
the same it's a different part number from Adavance. The 95' uses a
a BWD # WT655 or ACDELCO F1855 all from Advance. I expect that
your 96' gauge isn't the same as well.

As it stands now the information to this point would cover 91 through 94
Escorts. I'll try to do the 95' later.

AJ1G and dave8338 Thanks!!

Keep Your comments coming please!!!Lurkers time to Pony up!!
 

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Have not seen this addressed yet in the replies - are others seeing the big swings in temp gauge readings that I have seen when idling or in traffic with the AC/Defrost off?

Chris, Stonington, CT
 

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Discussion Starter #8
AJ1G,
Yes, I'm seeing those swings with my 91 Escort Pony Automatic but not
with my 94 manual. I'm particularly interested because I just replaced my
Cylinder Head due to a blown headgasket and don't want to repeat the
job.

After I intalled CTS "unit B" above from the chart, my Gauge deflected to
"M" (which is about 220F from my testing) during a short drive. I did't
hear the Radiator fan kick on, but it seemed to cool down after I hit a
open piece of road. It returned to just under "R" which is now about
207F I believe. It was approaching "M" agian as I made my way through
my neigborhood. All this was on my 91'

I think the FIRST step in understanding how all our Escorts cool is by fully
examining the operation of the CTS (Coolant Temperature Sending) unit
thus gaining a fuller knowledge of the Gauge Operation and what it's
actually communicating to us, flawed as it may be.

My Ponys lacks AC or Power steerring so I can't turn on the radiator Fan
at will as you and many other can, by turning on the AC or defrost. This
should not be needed of course in any case.

Ford used this Gauge in all versions of the 1.9L 2nd gen Escort until 95 I
think. Therefore it's reasonable to me with different factory options
installed, and taxing the coolant system differently, Ford needed a wide
range gauge. It resulted in a "NORMAL" range that seems a bit extreme to me.

I found this in passing on another thread and found it interesting...

"Vehicles built from 1/1/93 to 4/1/93 may experience high temperature
gauge indications which may have been due to the installation of
improperly manufactured temperature sending units. The customer
concern is that the gauge indication is beyond the letter "L" in the word "NORMAL". If this condition occurs, inspect the temperature sender
for an "A3" stamped date code on the hex of the sending unit. If an "A3" unit is found, replace with "NON-A3" service stock"

One thing I'd like to know is normally does the Cooling system in an Automatic run hotter than a manual?

I'll be looking at the ECT on another thread during the coarse of this
examination.

For now if everyone would report their guage operation it would help you
me and others. Mentioning if it's a Automatic, Manual, LX or Pony would
add to our knowledge. If someone would like to test their CTS unit
and gauge that would be even better. Whichever, please keep the info
coming!!
 

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awesome write up!
 

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Here's my tidbit for you guys...
My 94 LX Auto w/ AC and Power Steering tends to stay REALLY cold in the winter, usually touching N after 15 minutes of driving in Drive (not Overdrive... My futile attempt to warm up the engine to get heat). During the summer, if I'm moving, it's usually dead center between R and M. If I'm sitting in traffic without the AC, it'll go way past the L and hit the line before the red line. If turn the AC up all the way, it will cool down a bit, but it never goes down lower than L unless I start moving at a brisk pace (30+).

Hopefully that'll help someone. I can try the resistor experiment later if I ever get the car rolling again lol (see lower thread).
 

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Those resistors are way higher wattage than needed. I used a potentiometer:



If I had to use fixed value resistors, I would have used ones that look like this:



But then again, I've got tons of spare electronics parts laying around.
 

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Discussion Starter #12
zzyzzx-

You are absoluteley correct!

As I mentioned earlier mine are big "bathtub" 10 watt resistors. You can
get smaller physical sizes (wattage) but I found these easier to work with.
Further, I wrote the beginning so one didn't need a mulitmeter to measure
the ohm value on a potentiometer, just buy the resistors and twist
together as shown since the values are clearly shown on the part. Also,
no understanding of ohms law needed or working with the resistor color
code. I guessed that some people could safely use the larger wattage
resistor for other project if they wanted too.

BTW, I've had a few cheap potentiometers to actually read higher than 10
ohms at minimum value rotation, which was another reason I choose standard resistors. Your 1/8th or 1/10 watt? resistor is a 440 ohms I think.

Again you're right, these other parts you've noted will do nicely but may
require a little more experience and technical know how . Thanks much for the input and pics!

By the way what were your results?
 

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You guys are having way too much fun with this... :lol: :lol:

Keep it up !
 

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Discussion Starter #15
Did some more testing today. Was able to obtain OEM examples
of both a CTS unit and an ECT. They were not cheap. Here is a
chart showing the OEM CTS unit ohm readings along with averaged
ohm readings for all previously tested CTS units including the OEM
CTS unit all vs Temperature.



You'll notice I had to do some estimating at higher temperatures. I think
they'll be confimed through experience or further testing.

With this information one should be able to make a reasonable estimate
of what our stock temperature gauges are telling us. For Instance;

- at "C" you're at 145F.
- you're about 170F at the first vertical line preceeding the "N"
- past center you've most likely exceeded 212F
- at "L" I'll estimate you've certainly exceeded 230F
and you Radiator Fan should have been activated by this point.

If you guys could PLEASE confirm or dispute this paragraph above
It would be very helpful.

Additionally I've spotted what I believe is an error in the Haynes Repair
Manual. It says "Heat the water to 176F.....If not approximately 9.7 ohms,
replace the sending unit." From what I see 176F would produce an
averaged reading close to 45.7 ohms which is produced at 175f.
I believe their intention was to test for full deflection of the Gauge.
I was never able to get any of the CTS units to even close to 9.7 ohms.
 

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topfile said:
zzyzzx-

You are absoluteley correct!

As I mentioned earlier mine are big "bathtub" 10 watt resistors. You can
get smaller physical sizes (wattage) but I found these easier to work with.
Further, I wrote the beginning so one didn't need a mulitmeter to measure
the ohm value on a potentiometer, just buy the resistors and twist
together as shown since the values are clearly shown on the part. Also,
no understanding of ohms law needed or working with the resistor color
code. I guessed that some people could safely use the larger wattage
resistor for other project if they wanted too.

BTW, I've had a few cheap potentiometers to actually read higher than 10
ohms at minimum value rotation, which was another reason I choose standard resistors. Your 1/8th or 1/10 watt? resistor is a 440 ohms I think.

Again you're right, these other parts you've noted will do nicely but may
require a little more experience and technical know how . Thanks much for the input and pics!

By the way what were your results?
I used to be an electronics technician. The color bands on the small resistor I showed were not to be taken literally! The way I tested my gauge was with a potentiometer to ground and I watched my gauge sweep across as I moved the potentiometer. Probably more fun to do than your method as well. For the most part for stuff like that I just us excess electronics parts I have laying around. Seriously, this is the easiest gauge on the car to test!
 

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mine stays cold

My 94 LX W/Air, manual always stays cold. It does not even get to the "N". I tryed to replace the sensor, but it wouldn't budge. The fan will kick on using Air, but I cannot hear it while driving.
 

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Likely cause of the issue...
https://www.google.com/?gws_rd=ssl#q=site:feoa.net thermostat housing

Vehicle uses one temp sensor for the ECU + engine fan. The other temp sensor is for the gauge. I have a 94 LX w/ air and have never had issue out of mine. Fan consistently activates at or just before the middle (50%) of the gauge. (rarely gets there) High speed activates around 70 or 75% of the way.

Infrared temperature readers can be cheaply had. Just point at the head, (not the valve cover.) Just check and make sure that it's capable of reading at least 230 degrees. The really cheap ones (not designed for auto use) won't go that high.

EDIT: Whoops. Looks like the thread was bumped due to spam (which has been deleted).
 
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