Running temp.

Jump This · Jul 5, 2006

I've had my Jeep for a few years now, I know that 220 is just not that hot.
But recently I replaced my temperature sending unit (the one near fire wall) and now I'm getting readings of 230 plus...most of the time.
What I find interesting is that it doesn't feel that hot. So.....I barrowed an infrared/wireless temperature 'gun' and was only getting readings of 208* at the thermostat (obviously reading on the outside of the housing.) Readings at the radiator of 180* and 190 at the hoses.
Has anyone had this sort of problem before? Its my guess that the sending unit is reading about 10* hotter than what it is....:dunno:
What ya think?
Rick R

ROADLESS · Jul 6, 2006

Put the old sending unit back in (if it still works) and compare temps from same locations.

cracker · Jul 6, 2006

Jump This said:
I've had my Jeep for a few years now, I know that 220 is just not that hot.
But recently I replaced my temperature sending unit (the one near fire wall) and now I'm getting readings of 230 plus...most of the time.
What I find interesting is that it doesn't feel that hot. So.....I barrowed an infrared/wireless temperature 'gun' and was only getting readings of 208* at the thermostat (obviously reading on the outside of the housing.) Readings at the radiator of 180* and 190 at the hoses.
Has anyone had this sort of problem before? Its my guess that the sending unit is reading about 10* hotter than what it is....:dunno:
What ya think?
Rick R

You should have disclosed you live in a firey inferno :lecture:

Jump This · Jul 6, 2006

cracker said:
You should have disclosed you live in a firey inferno :lecture:

Okay...so there is THAT!
But still...
The old unit took a dive during some other work....
although the sudden rise in running temperature does coincide with a sudden rise in the heat and humidity...as well as with the installation of a new temp sending unit....I'm left thinking its a sender issure...just checking if I'm the only one in all of NAXJA

that has experienced this malady....

Rick R
(hey, its raining outside and the temp is down to 100*...ya HOOOOO!)

ROADLESS · Jul 6, 2006

Yes, i have also experienced this on son's 88 XJ. After changing the sending unit, the guage was off by about 10 degrees (can't remember if it was higher or lower). When we replaced it we used OEM sending unit from the dealership.

XJ4PLAY · Jul 6, 2006

You are reading temperatures with the infra red unit at different places than the sending unit you replaced is reading at.
Did you try reading the temp, with the infra red unit, at the sendind unit to compare readings? This would be more apples to apples readings then what you already did.

Just my .02

MrMom · Jul 6, 2006

I have latlely been exsperiencing the same thing just replace the sending unit
and I keep thinking she is running hot but I need to add a another temp guage to compare... any one know the exact temp the elec fan should come on and the temp the mechanical fan should begin to lock up?
this would help me out

cal · Jul 6, 2006

I saw something like this on a kids jeep I worked on a few months ago.. all new head and cooling system, his temp gauge read pegged about the time the thermostat opens. replaced the sender, and it reads 230-240 at running temp, but feels normal.

Jump This · Jul 7, 2006

I have checked the temperature using the infrared at many places, just trying to find anyplace running at 230* but have found only one...those damn exhaust headers get cookin'!

I'm just not going to worry about it anymore, I have decided its reading hotter than it actually is....but I'm still carrying around an extra gallon of water just in case (I always do during the summer anyway.)
Thanks for the help.
Rick R:sunshine:

XJ4PLAY · Jul 8, 2006

MrMom said:
I have latlely been exsperiencing the same thing just replace the sending unit
and I keep thinking she is running hot but I need to add a another temp guage to compare... any one know the exact temp the elec fan should come on

"... approximately 218*F. At 209*F the fan shuts off..."

MrMom said:
and the temp the mechanical fan should begin to lock up?

there is no specific temperature.
"... engagement should start to occur at between 165* and 180*F. Disengagement should start to occur between 135* and 175*F..."
These temps. refer to the air temp coming accross the radiator and contacting the viscous drive.

Running temp.

Jump This

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ROADLESS

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cracker

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Jump This

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XJ4PLAY

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MrMom

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cal

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Jump This

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XJ4PLAY

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