Coolant Temp Sender 1998 5.4L 2WD ( my version of reality )

[vigman]

Thought I would share this info…. might help someone down the road…

My Expedition has had a rather abused prior life ( maybe you have read some of my previous posts ) .

My engineer background would NOT let this slide. The temp gauge on the dash reads LOW… and it just BUGGED ME.. THe cooling system still needs some LOVE.
Heater plugged in front, rear one blew & is currently bypassed. Radiator is new about 2/3rds of the cooling system hoses have been replaced. As far as the Scanner is concerned.. it runs at the proper temp.. BUT THAT GAUGE… GAHHH.

So I thought I would TRY to save a few bucks. Going forward NEVER going thru that again.. It started, harmlessly enough ( I THOUGHT ) with a 20 dollar JC Whitney ( CRINGE ) coupon and the sender I " thought " I needed was 22 bucks, So I ordered it. ( Mistake #1 ) I ordered one for a 4.6 not the 5.4.

I sent an E mail back to JC showing their sender ( out of the box ) to show the connections & a picture of my original sender and it's connector. I asked if they could make a recommendation on what the proper sender part # would be and fully admitted (upon review) I had ordered the wrong one.

Their reply was "Since the part is already broken, we are afraid we cannot process replacement or refund for this." wrapped in a Oh HELLO, we aim to please , we're so sorry… There I am thinking WTF??

I called their 24 HR " Service line " Located in the Phillipines !

Asked them to pul up my email ( they did after the YAK pulled win 95 machine decided to work ) . After 10 minutes of " I NEVER installed your part.. the 2 other pictures was to show you what was CURRENTLY under the hood" CLICK the light bulb went on and I was issued an RMA and a free return shipping label.

Score so far job 1/2 done ( had to pull air intake snorkel ) to get to the connector of the CTS and put it back when the connector was different.

On to Chapter II

 

[vigman]

CTS and you… Chapter 2

The 4.6 L CTS arrives back to NYC and 4 days later I get a FULL REFUND ( 22 bucks and change ) into my Pay Pal account .. WOW did you FORGET 20 was in coupon form?? It's like printing your own money… So I re did my research, ordered what their Cross reference sheet "Stated" was the correct sender ( Wells TX-61 ) and ordered that one $18.95 FREE SHIPPING !

What could possibly go wrong??!!

3 Days later new part arrives.Yesterday it went in ( FYI the truck drew first blood of the morning ) It was a SIGN !

I inspected the new sender, connections look OK, thread size looks OK.. and in we went.. 20 min later… test… NADA on gauge after 5 min at idle… Hmmmmm

Went to post office ( with scanner hooked up ) .. Coolant temp 205 dash gauge ZIP-ZERO-ZILCH-NADA..

Just an FYI when I pulled the OLD sender out ( 19mm wrench or DEEP 6 point socket ), My truck was converted by a previous owner to an aluminum intake YEAH!

The " riser " where the sender screws into ( when COLD ) burbled up just a little coolant, the tip of the original sender was covered in RUST and other BLECH… AND what is rule #12.. NEVER TOSS YOUR OLD PART OUT TILL THE REPAIR IS COMPLETE.

So faced with this I did some SCIENCE !

Chapter 3 ( Show your work )

 

[vigman]

Chapter 3 Blinded em with SCIENCE

Now the shop manual states to jump the 2 pin connector for the CTS ( female side ) and see if your dash gauge reads FULL HOT, when turning the key on..
Did I do that NOOOOOOOOO that was to easy…

What I did do was a bit more precise…Used resistors to see what the sender .. sends ( and If I had 1/2 a brain I should have gotten a variable resistor out and mapped it better… must have been all the blood loss! )
Inserted a 1K resistor into the connector , gauge reads at bottom of cold
Inserted a 330 ohm resistor ~ 1/4 way into the cold zone…

Original FORD sender at ambient air temp 70 degrees 2k.
Reinstalled the OE sender in to the cooling system with 165 degree coolant 298 ohms
and ALOT of coolant burbled out so have to be FAST on the trade out!
BTW the original FORD sender part # is F-65F-10884-AA for the 5.4 L

The Wells sender: TX-61
COLD 24K WTF?
@ 167 4K
( Gee I wonder WHY the gauge didn't move DUH! )

So either I had a CRAP PART or WRONG PART !

Chapter 4.. the letter

 

[vigman]

Oh moe nyuck nyuck nyuck doink owwwww

So we have now done the " job " 3.5 times.
It's still not "FIXED".
But NOW we have some FACTS..

To JC Whitney Re Defective sender
I'll make this simple as I can, I'm an electronics engineer and have been working on cars since High School ( I'm 57 now ). I installed this part and it doesn't work.,AT ALL. Electronics 101.. a sender for a gauge has a resistance value, that resistance is translated to a voltage, and that is what is fed to the gauge to make it read HOT or COLD. Resistance is measured in OHMS. The Higher the resistance the less voltage and the lower the resistance , more voltage is sent to the gauge. Simple Huh? This is for a 1998 Ford Expedition 2WD 5.4L Eddie Bauer.The FORD part number F-65F-10884-AA
Ford sensor when COLD measures~ 2K (2000 ohms)
Wells TX-61 measures 24K ( 24,000 ohms )
At 165 ( ish ) degrees…
The Ford measures just under 300 ohms.
The TX-61 measures 6K ( 6000 ohms )
So either I have defective part or WRONG part.
The initial reason for sender replacement the gauge read ~15% low.
Enclosed are pictures to show my work.
Let me know how you would care to proceed.
Thanks
Mike

Chapter 5 the E mails

 

[vigman]

Ping Pong with E mails… chapter 5

They replied with:
Greetings!

Thank you for contacting us.

We are sorry to learn that the Standard Motor Coolant level sensor that you have received seems not working for your 1998 Ford Expedition Eddie Bauer. For us to assist you further, please provide the Part Number or the Partslink Number of the item that you received. It is indicated on outside the shipping box or on the plastic wrapping the item wherein a sticker label was attached and/or on the packing slip.

I sent ear jcwhitney,

I see no "Partslink" number on the shipper or the box .
But maybe if I had an example , I would know what I'm looking for...
The is PO# XXXXXXXX
Attached is a pix of a label on the box is that the # you are requesting?

No comment on the R&D for cause & effect ?
Did you agree, disagree? Did it make sense to you ?

Thank you,
Mike


And SCIENCE BLINDED THEM

"To save you from any further hassle, we have decided not to have you return the part anymore. You may dispose of it as you please.

A full refund of $19.84 will be processed so you can re-order the part again. This will go back to the same account where you were charged originally for this order. Our standard credit time takes 2 to 7 business days.

( which I got the FULL refund yesterday )

Chapter 6 conclusions

 

[vigman]

The CONCLUSION ( Chapter 6 )

I'm retired, so I have time to putz with this stuff. I'ts like a puzzle with a bear trap in the middle which I step in with GREAT FREQUENCY !

1) If I REALLY did my homework , the Ford dealer down the street had the OE part for $ 23.50.

2) I will be doing the "JOB" 4.5 times. it's not that tough, it did show me some other area's that need love & attention.

3) I learned something NEW.. If your temp gauge isn't working ..pull the fracking connector , jump it with a paperclip if it shows full hot, your cluster is FINE.Just replace the sender. ( I was put off by all the ..Well your cluster averages the CHT ( cylinder head temp sender ) and the CTS THEN sends that to the gauge.. BAH. The shop manual states if the cluster is bad it SHOULD throw a code.

4) My sender was ~ 15% off, and now it's CLEAN and some rust burbled up & out when I was a bit SLOW on the sender change. I need to drive the truck again to actually SEE what the dealio is.

5) There is NO substitute for factory parts in SOME applications.

6) ( see 5 )

7) Even though I made a FEW $$$ ( to pay for the correct part ) the knowledge is a good thing.. Especially these days where there are VERY FEW counter guys who KNOW THEIR SHIT !

8) My assumption ( knowing all this..NOW ) is the OE sender has drifter over time, and that is the reason for the inaccurate reading. ( still to be proven ).

I hope this helps someone…
Mike

 

[Bowesmobile]

LOL, thats a good write up. I have the same problem with my temp gauge. I replaced the sender with a Advance auto unit and it still doesn't work. So now I know its probably the sender not the instrument panel. My solution for the time being was more fun though. I have a tablet and the Torque app. I use that as my instrument panel and forego the crappy factory gauges with literal values coming into the computer.

 

[vigman]

Bowes,, quick & simple test... just short the 2 sender pins on the female side... if the gauge goes UP it's the sender. The Torque app will give you " calculated " coolant temp.. same with a scanner....

 

[Bowesmobile]

Yes you're right. The app has been getting me by. I am replacing the motor this weekend and I'll see if the new motor has a good engine temp sensor.

 

[Bedrck47]

Bowes,, quick & simple test... just short the 2 sender pins on the female side... if the gauge goes UP it's the sender. The Torque app will give you " calculated " coolant temp.. same with a scanner....

Question What does it mean if you short the 2 pins and the gauge doesn't go up??

 

[vigman]

According to the shop manual it's cluster replacement time ( if memory serves ) ...

 

[Bedrck47]

could it also mean that there is a open circuit in the wiring

 

[vigman]

Yes that is very true as well....

 

[Bowesmobile]

Or it could mean that there's a time difference between the sensor and the intrument panel so it's sending the signal to the past! Or the future! Then again...probably not.

 

[vigman]

Final chapter I HOPE…
The new sender arrived I went to install it ( Stupid truck drew first blood … AGAIN ) …
I did the sender socket jump with a paperclip, FULL HOT.. Sender swapped and it came up a lot faster then " normal ". Only let it get 1/4 ( didn't want to burn fuel just sitting there since I have errands to run ). The final test approaches

 

[vigman]

Well the sender portion is done …BUT...Well PARTIAL WIN.. the gauge now reads correct BUT the engine runs COLD.. If I get the truck up to temp and PARK ~ 5 min.. SLIGHTLY over half ( which is correct ) BUT If I restart the truck it drops t about a 1/3 rd in ~ 15 seconds. So either I have a POS thermostat OR a way to MONGO fan & clutch + a bad stat… more research is needed!

 

[vigman]

New OEM stat on the way with O ring….

 

[Mark Burns]

This sounds just like the problem I'm having. We bought a used 98 Eddie Bauer. The gauges were malfunctioning due to a bad temp sensor. I bought another one online from Amazon and installed it. Now the gauge won't even move. It stays at the bottom. Did the whole shorting of the lines and the gauge works fine. Bought another sensor from Napa thinking that maybe my online sensor was bad. After a lot of searching and videos I think I have come to the conclusion that aftermarket sensors have too high a resistance. Both of my aftermarket sensors read about 24 to 25K when cold and only drop about 5K when heated in boiling water. The next step is heading to the Ford dealer and finding out if the OEM reads a lower resistance. I couldn't find any other reason, besides the high resistance, for the gauge not to work. I will come back to this thread in a few days and let you know what I found.

 

[Mark Burns]

Okay, did some research and e-mailed a bunch of experts. Finally found a local Ford mechanic that actually knew what I was talking about and confirmed that the auto parts stores were all selling me the wrong thing. Turns out that the coolant temp sensor that I needed was actually called the coolant temp sender. The replacement part was TS-380 vice the sensor which was TX-61. I ohm'd out the part and it definitely reads about 2.7k ohms vice the 25k that the other part reads cold. The two units look almost identical and unless you knew that the parts were for different uses in the vehicle no one would be the wiser. The TX-61 is for the engine management computer to read and the other one just sends the actual temp signal straight to the dash gauge. I am replacing it this weekend and will let you know what I find.

 

[Bedrck47]

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