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another temp thread.

O

outlander

NAXJA Forum User
Location
Columbus,Ohio
89 xj 4.0 with closed cooling conversion.

I recently hooked up an aftermarket electric sender temp gauge and noticed that it is reading about 212* when the jeep is at operating temp while the factory gauge is saying 205 ish.
Now I have to believe that the factory gauge is the liar here so I bought a non contact infared thermometer and am looking at verifying the temps to figure out which gauge is lying.
Where is the best place to take the reading from?The thermostat housing or the upper hose or somewhere else?I'm trying to get a true coolant temperature reading.
 
wouldnt the coolant be at a different temp depending on where it is in the cooling system. so your not going to get a true reading.

is the gauge you installed in the same place as the xj sending unit.

the sending unit for the electric fan is in the bottom of the radiator, so i would think thats where it would be the hottest.


seems like your really splitting hairs.
 
The after market sender is installed into the thermostat housing.....is it possible that there is such a temp difference between the location of the factory sender(located at the back of the head)and where I have this one?I had pondered that while installing the after market sender.

Going out in a few minuets to play around with the infared thermometer....
 
The upper hose, if you can get a true reading through rubber, should be the hottest since it hasn't had a trip through the radiator to cool.

But really 7 degrees is not that much of a difference especially on a factory gauge. If your "coolant temperature sensor" (the one under the manifold that gives the computer it's info) is sending the correct information then 205ish is really 210ish, which is pretty dang close to 212. It seems to me that an ifrared thermometer is going to vary at least that much depending on where you point it.

If you take the reading at the t-stat it should read dead-on the same as the aftermarket gauge is telling you if the infrared is accurate.

Why did you put in another sensor?
 
Last edited:
ParadiseXJ said:
The upper hose, if you can get a true reading through rubber, should be the hottest since it hasn't had a trip through the radiator to cool.

But really 7 degrees is not that much of a difference especially on a factory gauge. If your "coolant temperature sensor" (the one under the manifold that gives the computer it's info) is sending the correct information then 205ish is really 210ish, which is pretty dang close to 212. It seems to me that an ifrared thermometer is going to vary at least that much depending on where you point it.

If you take the reading at the t-stat it should read dead-on the same as the aftermarket gauge is telling you if the infrared is accurate.

Why did you put in another sensor?
Click to expand...

x2

the important sensor is the one on the side of the block, that sends a signal to the ecu and the one on the radiator that turns on the eclectric fan

there is going to be a difference between the temp at the thermo housing and the stock sender on the head. im not surprised that you got different temps there. it seems that both your sender gauges are correct.

to test a temp sender, you need an ohm meter and a chart.

goto www.lunghd.com and you can download the renix fuel injection manual.
 
Hallo.



I did a test of my temp gauge.
I used a replacement ohm value tool. 60 Ohm is 125C, 100 Ohm is 105C.
So I found out my gauge is ok, but my sender was broken.

FSM says 100F (38C) 1365 Ohm
220F (104C) 93,5 Ohm
260F (127C) 55 Ohm.

It is a one wire sender to make contact to the chassis. :spin1:
 
wim hoppenbrouwers said:
Hallo.

http://www.fototime.com/pictinv/25656055CB3789F

I did a test of my temp gauge.
I used a replacement ohm value tool. 60 Ohm is 125C, 100 Ohm is 105C.
So I found out my gauge is ok, but my sender was broken.

FSM says 100F (38C) 1365 Ohm
220F (104C) 93,5 Ohm
260F (127C) 55 Ohm.

It is a one wire sender to make contact to the chassis. :spin1:
Click to expand...

So, instead of testing the sender with an Ohmmeter, you tested the gage with this ohm sending device? Sounds expensive.
 
Hallo. Yes, I did this in an opposite way.
It is a pain in the @@@ to take out the sender and put it in boiling water.
Now I can do an accurate test with different temps/resistances with no problems and very quick. How to do a test with 260F or 100F? You will need a temp. device. LOL


p.s. Ohm value tool only costs 5 euros. :spin1:

 
Last edited:
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