Running HOT! the Temp Gauge LIES!

[rustynuts]

I'm with Rainmain with a scanner. If I am correct your car has two temp senders. One for the gauge and the other for the PCM.
I use a cheap ELM327 dongle that bluetooths to my phone or tablet. It has been one of the best things I have bought for my car.

[awg]

on my pre-update '96 there is one wire.

A new Jeep sender is +$40

i been thru this with other dudes, i cannot tolerate instruments that are not reliable

do yrself a big favor and spend the $25, dont throw away any old parts though, as you can revert in a trice.

my digital instruments tell me EXACTLY what the temp, oil pressure, volts are, not some approximation. (only have the coolant temp on Jeep)

worst come to worst u wasted 25, spill that much drinking

a DVM for instance is a VERY accurate & instant way of telling your battery or alt is on its way out, a needle gauge is next to useless

[awg]

one other thing my digital gauge help me sort.

after reading Rodgebones cooling Faq, he has obviously used a scan gauge on jeeps to monitor coolant temps

so i thought 105-112C was ok, as my gauge would read that sometime. (as he stated)

since doing NOTHING ELSE, but a very thorough bleed, it has never since exceeded 98C

this strongly suggests to me that any air in the system causes an issue, some vehicles are known for this...maybe jeep xj?

another poster listed his extreme method for doing this task

[junglejuice]

This is for you lulu.....



Even a vague gauge will still read in the right direction, ie if the temp goes up the gauge will go up, I find it highly unlikely that the gauge will read in reverse sometimes....

[werd]

Perhaps a really small leak. Just enough to not hold the pressure. With the heat the coolant evaporates. But get a uv light and check everything and if there is a leak, you wI'll find it. Even inside for possible heater leaks.

Temp guage test:
COOLANT TEMPERATUREGAUGE The diagnosis found here addresses an inoperative
gauge condition. If the problem being diagnosed is related to gauge accuracy, be certain to confirm that problem is with gauge and not with cooling system performance. Actual engine coolant temperature should be checked with a test gauge or thermometer and compared to gauge readings before you proceed with gauge diagnosis. Refer to Group 7 - Cooling System for more information. (1) Turn ignition switch to ON. Disconnect coolant temperature sending unit connector. Sending unit (Fig. 1) is located near the left rear corner of the cylinder head. The gauge needle should move to low end of gauge scale. If OK, go to next step. If not OK, go to step 3. (2) Install a jumper wire from sending unit wiring
to ground. The gauge needle should move to high end of gauge scale. If OK, replace sending unit. If not OK, remove jumper wire and go to next step. (3) Turn ignition switch to OFF. Disconnect battery negative cable. Remove instrument cluster bezel and cluster assembly. Disconnect gauge cluster connector A.
(4) Probe cavity A1 of cluster connector A. Check for continuity to a good ground. There should be no continuity. If OK, go to next step. If not OK, repair short in circuit as required. (5) Still probing cavity A1 of cluster connector A,
check for continuity to sending unit wiring connector. There should be continuity. If OK, replace gauge. If not OK, repair open in circuit as required.

[LuluBelle]

I am going to revisit the cooling system because its weird
the entire cooling system is NEW everything and the fans are not backwards the red xj 99 sits on 98 and wont move I have a infer red temp gun and there is about a 5 to 8 deg difference shooting at the sender at the rear of the engine I will replace it and when I fit the new tranny cooler I will have a good look at the aircond rad to see if its blocked restricting airflow I don't know as I never regassed my aircond last on the long list..........
once again thanks for everyone's input........
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