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Why won't it warm up?

95YJman

NAXJA Forum User
Location
Fort Wayne
My Jeep won't warm up to operating temp, its had a new thermostat, water pump and the radiator tested. It still blows hot air for the heat though. So its not really affecting anything:dunno:
 
So its not really affecting anything

depending on what weight oil youre running and what temperature your engine is actually getting to, it may not be a sufficent temperature for the oil to break down to its best protecting ability (i.e not so great for your engine)

also remember that the temp gauge in the dash isnt necessarily the most accurate

i would personally start with trying another new thermostat since theyre cheap
 
What temp thermostat?
 
I'd replace your temp sender that controls the dash gauge. Can't remember if that's the one at the front of the block, or in the back....
 
sending unit for the gauge is on the top, rear of the head next to the valve cover on the fuel rail side. it is a one wire curcuit. check to make sure it is making good connection to the sending unit.

to test the gauge, check its resistence. i believe lunghd.com has the a chart for the resistence values.
 
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its a 92, the thermostat I put in it is a 195, I'll check out the gauge sender unit. See what I find! heh Somebody wouldn't happen to have a picture of what it looks like and its exact location would they?
 
get a temp gun...or just let it run...is it hot? get a temp sender if its not reading on the gauge.
 
After it reaches it's highest temp, how long can you hold the heater hoses for? If you can hold them for 30 seconds without extreme pain, your not getting hot enough. If you can, it must be a tstat problem.
 
Well I replaced the sensor and checked the wiring while I was at it, the wiring is good. I did also hold the heat gun to it. It is reaching operating temp so the gauge is off. With the new sensor it reads a little more better but still off heh. I may replace the T-stat. Right now I'm just gonna leave it alone it runs good, and I have heat. Thanks for the help everyone!
 
Well I replaced the sensor and checked the wiring while I was at it, the wiring is good. I did also hold the heat gun to it. It is reaching operating temp so the gauge is off. With the new sensor it reads a little more better but still off heh. I may replace the T-stat. Right now I'm just gonna leave it alone it runs good, and I have heat. Thanks for the help everyone!

Did you use any sealant on the threads of the sending unit? As posted earlier, a single wire sender/sensor needs its ground through the surrounding metal.
 
My sensor never worked. Jeep always ran fine.

Then I put it in storage for 1.5-2 years. Once I took it out storage I fired it up and the sensor works fine now. Looks like my Jeep just needed some time alone in the corner to realize what it was doing wrong. :D
 
yep used some sealent on the threads so it wouldn't leak...

Too much sealant (some say any sealant) on a single wire sender/sensor will screw with its grounding and skew its readings. Quick check, attach a wire to the sender and a good ground and see if the readings change.
 
Well I replaced the sensor and checked the wiring while I was at it, the wiring is good. I did also hold the heat gun to it. It is reaching operating temp so the gauge is off. With the new sensor it reads a little more better but still off heh. I may replace the T-stat. Right now I'm just gonna leave it alone it runs good, and I have heat. Thanks for the help everyone!



How far "off" is it? I mean if your running at like 190*-195* your about there.
 
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