Coolant Temperature Sender

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john keefe
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Re: Coolant Temperature Sender

Post by john keefe » Fri Aug 02, 2019 4:30 am

brokencase wrote:
Thu Aug 01, 2019 11:52 pm
If you look at all the sensors they sell for the model in question you will see there is a green one, a red one, and a black one...etc... They all work the same.
Seems so. I'll stick with colors likely reflecting different OEM manufactures.

I installed one of the new green ones today. At first, no response at all. Great. But then I knocked on the instrument cluster and it started working... Go figure. :D

At idle, reads high (above the N in NORMAL, but still within the white box. The old one read just a bit higher than mid of NORMAL. Probably need to swap out the fan clutch, but we'll see what happens when I can drive it around and get some air flow through the radiator.

brokencase
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Re: Coolant Temperature Sender

Post by brokencase » Fri Aug 02, 2019 8:51 pm

Be careful. Double check with another temperature measuring tool if there is any doubt. You don't want to overheat it. Definitely get the fan clutch fixed if it is bad.

The sensor I got from Latvia was dead center of the gauge once the engine warmed up.

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Re: Coolant Temperature Sender

Post by merkurdriver » Sat Aug 03, 2019 11:58 am

brokencase wrote:
Thu Aug 01, 2019 11:52 pm

If you look at all the sensors they sell for the model in question you will see there is a green one, a red one, and a black one...etc... They all work the same.
For the XR4Ti the only one that reads correctly is the one with the purple ring on it. (The black ring one reads nearly double.)
Probably why I'm so fixated on the colors of the senders being different.

Seems like these Scorpio ones might be a different story. You have sourced an inexpensive one that reads perfectly, so :cheers

john keefe
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Re: Coolant Temperature Sender

Post by john keefe » Sun Aug 04, 2019 3:09 am

Yeah, going to test resistance deltas on the other new one against a known good one. I'm a little suspect... doesn't matter if I'm at idle, in traffic, going 70mph, or with the A/C on or off, it still reads the same. At the high end of the "normal" scale.

On the other hand, this is the third time I've had to knock the instrument cluster above the temp gauge to get the needle to respond. Could be something a little off with the gauge itself.

Already put two new heads in it, and I'm pretty wary of any overheating as I don't want to redo that. Car doesn't run hot, though. Loud, typical rough V6, but not hot.

Not sure about the fan clutch, but it sure could be the next item to address.

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Re: Coolant Temperature Sender

Post by Ed Lijewski » Sun Aug 04, 2019 7:52 am

Re the fan clutch, with the right size nut removal tool (~$12 Ebay) and your own 13 mm closed end wrench, removal is a snap. Install a new one and sleep and drive worry free for 50-70K miles, and then install another new clutch.

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Re: Coolant Temperature Sender

Post by john keefe » Fri Aug 09, 2019 6:17 pm

Does this fan clutch require a 37mm wrench??? I mic'd 36.5mm on the replacement fan clutch out of the box, and 36mm doesn't work in socket, or box wrench. 37mm is a shade smaller than 1.5". No such size wrench out there on eBay.

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Re: Coolant Temperature Sender

Post by Ed Lijewski » Fri Aug 09, 2019 7:26 pm

Maybe I misspoke (from memory). I'll measure mine and post what it is in mm shortly.

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Re: Coolant Temperature Sender

Post by john keefe » Fri Aug 09, 2019 8:22 pm

if all else fails, I'll just get a 36mm, and grind it down a bit to fit.

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Re: Coolant Temperature Sender

Post by Ed Lijewski » Sat Aug 10, 2019 5:30 pm

The correct size fan clutch wrench is 36 mm.

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Re: Coolant Temperature Sender

Post by brokencase » Sun Aug 11, 2019 1:48 pm

Fits Fiesta, Escort..AND Scorpio. I know..I know...Hard to believe Ford actually used the same sensor across many models and dash gauges..
BUT THEY DID!

https://www.ebay.com/itm/OEM-Temperatur ... SwK6NbGQtr

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Re: Coolant Temperature Sender

Post by john keefe » Wed Aug 14, 2019 2:26 am

36mm, so why the heck do my 36mm's not fit the "OEM" replacement nut? I'll have to do some more investigation when I get back. Just seems improbable that somebody would install a 37mm nut on the clutch by mistake... I can't off hand think of any application for which I needed a 37mm wrench, which is why I don't own one. A rare metric size that doesn't translate to any SAE inch size (1.45").

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Re: Coolant Temperature Sender

Post by john keefe » Thu Sep 05, 2019 10:56 am

Finally had time to swap out the clutch fan. Good call on the $15.00 eBay wrench.

Weird... the old one spun off easily, in fact it was a few threads loose. The nut on the new clutch was a tick over 36mm, but a little grinding on the wrench solved that. Had to redo the install after discovering the screw holes for the fan weren't tapped all the way. Dubious QC, and I kinda' wonder how good the performance will hold up, but for now it works, and spins smooth.

So, it still reads up on the high end of the Normal scale, but holds solid. Acts normal (i.e., gains smoothly as temp increases). Again, it was the "green" base sensor.

I don't want to chase finding/trying other sensors, so I'll leave it be for now. At some point I will have to take apart the dash to fix the speedo gear. I'm wondering if it would be practical to put a resistor or something to step down the voltage reading to the gauge at the cluster. Not the signal at the sensor, but the wiring to the gauge at the cluster. Any thoughts?

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Re: Coolant Temperature Sender

Post by Bob Weir » Thu Sep 05, 2019 1:19 pm

<< At some point I will have to take apart the dash to fix the speedo gear. >>
To play with all the gauges, you only have to remove the instrument cluster [ 2 top & 2 bottom screws ]. Place steering in lowest position. The trick is first wiggle out the top of the cluster from the dash

<< I'm wondering if it would be practical to put a resistor or something to step down the voltage reading to the gauge at the cluster. Not the signal at the sensor, but the wiring to the gauge at the cluster. Any thoughts? >>
I never heard of adding a resistor to the gauge. Why do you want to step down the voltage?

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Re: Coolant Temperature Sender

Post by Ed Lijewski » Thu Sep 05, 2019 2:13 pm

Re temp gauge reading: I'd install a new (Motorcraft) T-stat and observe if the reading holds at a lower level.

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Re: Coolant Temperature Sender

Post by john keefe » Sat Sep 07, 2019 2:16 pm

Bob Weir wrote:
Thu Sep 05, 2019 1:19 pm
Why do you want to step down the voltage?
The action seems to be "normal," just high. If its just a matter a little higher reading because the Euro sensor is calibrated slightly differently for an ECU (for whatever reason), then stepping down the voltage to the gauge itself 25% or so would bring it back to mid-normal display. Wouldn't make a difference in performance, just reads better, and also gives me a better indication of when it really is running "hot," as opposed to running slightly hot and consequently displaying an overheat. If I'm going to chase an overheating situation, as with any sensor I'd rather know if its real, vs. just a display quirk.

Try as I might, I couldn't find a "real" Motorcraft sensor, and I put in a Motorcraft T-stat a couple years ago when I swapped out the heads and water pump.

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