Running HOT! the Temp Gauge LIES!

[LuluBelle]

Happy Easter .... But the title says it all.....On my recent trip to Brisbane apart from a loose earth wire on the LPG the Jeep never missed a beat BUT still on the highway it ran HOT never overheated but after say 5 hours of running when the day warmed up it was constantly kissing the RED...
While in slow city traffic it stayed cool..
...............Because
New Rad
New Thermostat
New Waterpump
New Clutch Fan
Professional Coolant Flush
Hood Louvers
Fan Override Switch
So it has to be the Temp Gauge Lying ...WHY! as to look at it at the rear of the engine it has 2 red wires running to it.................. not the standard wiring harness
A Friend recently told me that using a aftermarket sensor can differ in the voltage range and give untrue readings.....I gope this is so!
its going to be FUN to change but I will get a bit of wiring harness from the wreckers and the correct sensor and see if that gives me true readings ........................
Otherwise I got no idea why my XJ runs HOT!
Your thoughts after say 500 klm and aroung 5 or 6 hrs constant driving I had to run the fan override and turn the heater on to stay outa the RED! 30 deg outside ....................... IT must be the Gauge Lying!!
_____ooooo
/__l_l_,\____\,___
l_---l_l__l---[ ]llllll[ ]
_.(o)_)__(o)_)--o-)_)

[junglejuice]

The sender unit can be tested very easily, the sender can be changed easy enough, a little fiddly but not too bad.
The stock unit is a single wire sender....

The FSM shows how to test it and what the readings should be, it's the same for the OBD1 95 so you can use that FSM for details.

I coulda sworn it was mentioned ages ago about verifying that your temp sensor was reading correctly???

[awg]

why dont you solve the problem once and for all fit a $25 Ebay digital gauge & sender, screws straight into the hole (or maybe a simple adaptor), I love it, gauge still just taped to a-pillar

i did a writeup somewhere...u cant keep the original as teeing them makes them innacurate they must b fully immersed

gauge could be placed in cluster if so wish

[LuluBelle]

well JJ thanks for the info BUT this one has 2 wires running to it? Both RED!??
yeah exactly..............But as always I like thrashing it out here and Value everyone's input..............before I do anything.........................You Guys have HELPED ME so much over the years
_____ooooo
/__l_l_,\____\,___
l_---l_l__l---[ ]llllll[ ]
_.(o)_)__(o)_)--o-)_)
............................................
Big Edit Here ........................
What I forgot to mention in the first post was......
cruising after 500k or 5 ish hours at 100 k on cruise control when I happen to slow down for a Town or have to wait at roadworks the Temp Falls fast Faster if I have the fan override on ...........But soon climbs up when I return to cruising speed ??????
_____ooooo
/__l_l_,\____\,___
l_---l_l__l---[ ]llllll[ ]
_.(o)_)__(o)_)--o-)_)............................................... ...................

[junglejuice]

My usual stance is to repair before modifying, the OEM wiring only has 1 wire to the temp sensor, IIRC you have gas fitted, correct?
Maybe the gas system requires a seperate signal?
First confirm if the sensor is reading the correct range to suit the gauge but even if the range was wrong it seems strange that the temps drop at low speed, almost like your fans are running backwards because on the highway or at speeds of say 60+ the fans have no real effect, when I was on my way to the cape last year I turned the fans off as soon as I was out of town, fully loaded and towing a camper trailer....

[rustynuts]

Your running cooler when you slow down? That doesn't make sense.
I think it can be only two things. You have a fan pushing air forward instead of sucking it in or you are not running a thermostat resulting in too much water flow through the system at revs.

[rainman]

have you thought about getting a scanner?
on a 96 you can compare the PCM temp reading against the display on the dash.
they are cheap and imho, invaluable when working on 20yr old cars.

That said to me it suggests a air flow problem at speed, those vents you mentioned new?