Coolant Temp Sender | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Coolant Temp Sender


Explorer Addict
June 27, 2005
Reaction score
City, State
Year, Model & Trim Level
1998 Sport 4wd- V6 Sohc
The temp gauge on my Explorer Sport stopped working after some repair work to the thermostat housing. I am thinking the coolant temp sender is bad and want to replace it.

I am confused as most auto parts stores such as rock auto, have the Temp Sensor and temp sender in the same catagory. Are these screw in coolant sensors both the same or is there one specifically for the sender and one for the Sensor? It would seem the units are interchangable?

Also I am thinking that the temp sender on my '98 X sohc motor is the gray one on the right of the housing.

Any help is kindly appreciated :D

Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!

Not speaking from experience on your particular vehicle but I know on my 5.0 the one on the left is a 2 blade terminal and they made 2 different sensor with different pitch thread. One is black and one is white. And the one on the right is a single blade terminal sensor. So to answer your question no they are not both the same, but they do the same thing "accurately measure temperature". I would take it off and go to the auto parts with it. Hope that helps you.

the gauge sender has one wire. the coolant temp sensor has 2.

This is very helpful, thanks much. I am going to check this out tomorrow and look for the single wire! When I looked earlier, it looked like both sensors had two wires??

Is there another way of telling which is which?

I have the two original coolant senders/sensors that came with the car still installed one is gray and the other is red. The one closest to the drives side is gray, that is the one my manual says is the Coolant sender.

If I could find out what color the original sender that came in a 1998 V6 sohc is that would narrow it down.

Guage should only have one wire - Red with White stripe; I suppose there could be a separate ground wire - that would be black.

ECU sensor wires are Light Green w Red stripe and Grey with Red stripe.

Hope this helps - good luck.

Thanks Bob, I am going to give this a go tomorrow :D

This is strange because both of these sensors have two wires, Neither one has one wire as people have stated.

This is a 1998 sohc v6 motor.

I checked the wires, the harness on the sender to gauge is green wire with a red strip the other wire in this harness is solid black.

It seems as if the harnesses were swapped mistakingly by the mechanic, is this possible? Would the truck run normally?

When I gave him the vehicle to work on, the gauge was working. Could the sending sensor go bad just from swapping it into another thermo housing?

Im so confused :banghead:

sensor wiring

I don't have a 1998 wiring diagram but the sensor wiring should be the same as my 2000. The engine coolant temperature (ECT) sensor sends the engine coolant temperature to the PCM. One wire is gray with red stripe and the other is light green with red stripe. The engine temperature sender sends the engine coolant temperature to the instrument cluster. One wire is red/white stripe and the other is black with a white stripe. The 4.0L OHV V6 doesn't have the black with white stripe wire because the sensor is internally connected to the threads and is grounded thru the engine. The thermostat housing for the SOHC V6 is not metallic so it requires an external wire for ground. Using Teflon tape for a seal won't effect the ground which is external. The sensors look similar but the connectors are keyed differently and thererfore not interchangeable with the mating connector. As I recall the ECT sensor is toward the driver side and the engine temperature sensor is near the passenger side.


Thanks for the Great info Streetrod, this is extremely helpful!

In your picture of the thermo housing what color is the temp sender to gauge?

swshawaii, thanks so much for the link this is going to make swapping it out a breeze!

If any body has done this does the upper intake have to come off or can I just take of the throttle body and upper thermostat housing?

Extremely greatful for the info :biggthump

Look at your car.
The sender for the dash gauge will have a black wire (ground).
The sensor for the PCM doesn't have the ground connection.
Also, in the scribd document, the right one is labeled as the temp gauge sender:

Excellent thank you Sonic, this is exactly what I needed! :)

Before I attempt this repair can someone who has done it tell me if it is better to remove the upper intake or to remove the intake tube, TB and upper thermostat housing to get to the sender?

Removing the upper intake manifold seems like a lot of work?

Thanks in advance for any suggestions :thumbsup:

poor design

You should be aware that the thermostat housing is a poor design that is susceptible to cracking and leaking coolant. Also, since it is not metallic, threaded inserts are used for the sensors. Often when replacing the sensors the insert will spin in the housing and then leak. Ford eventually changed from screw in sensors to clip in sensors. There are threads on the forum about upgrading from screw in to clip in. The upgrade requires purchase of housing, sensors and clips. Recently an aftermarket metal housing became available for the Mustangs with one sensor and eventually a two sensor version for the Explorers. I replaced my stock plastic housing with the metal one but it wasn't cheap.


At least one forum member reported replacing the sensors without removing the upper intake manifold but said it was difficult. If you've never replaced the upper intake manifold gaskets they're probably leaking so replacing them should be worth the time.

I suggest that you confirm the sensor is bad before replacing it and risking a leaking sensor insert. The locking tabs on the sensor connector break with age and use. The connector may be loose or the wires to/from the sensor may be broken. I don't have a 1998 wiring diagram but on my 2000 the sensor resistance to ground can be measured from C115 pin 16. C115 is the engine wiring harness main connector in front of the coilpack.

Thanks Streetrod this is a huge amount of excellent information. That new housing looks awesome and I'm thinking of going that route.

Thanks again for all the great info

Thanks this looks very interesting and worthwhile permanenet fix

This is an old thread but the intake manifold does not have to be removed.

After replacing my housing the temp gauge does not work. Anyone know which sensor operates the gauge? Driver's side or passenger's side?

Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!