XJ is wanting to overheat.
#17
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Year: 1991
Engine: 4.0 I-6 H.O.
I think you should try the 180*F Tstat. I tested 6 thermostats from 3 different suppliers,
Napa, Chrysler and Stant, 2 from each. All of them stamped 195*F, all them opened at 205 - 210*F. So brought home a 180*F Tstat and it opened exactly at 180*
What are you going do? (and my thermometer is very accurate)
Your Aux fan is a good back up but the Rad. should do the job 90% of the time.
I assume your 91 xj is what this thread is about so your either running renix or OBD1
neither of which will be affected by a 180* Tstat.
Napa, Chrysler and Stant, 2 from each. All of them stamped 195*F, all them opened at 205 - 210*F. So brought home a 180*F Tstat and it opened exactly at 180*
What are you going do? (and my thermometer is very accurate)
Your Aux fan is a good back up but the Rad. should do the job 90% of the time.
I assume your 91 xj is what this thread is about so your either running renix or OBD1
neither of which will be affected by a 180* Tstat.
oh well
#18
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Year: 1996
Model: Cherokee
Engine: 4.0 h.o.
replace radiator?
if you have not done it already....replace the radiator! the 4.0cooling system isnt very good in the first place and the radiators tend to plug up . i replaced just about every thing on my 96 cherokee country cooling system except the radiator...still over heated . replaced radiator add now no prob also dont forget about clutch fan ,those wear out so slowly you wont even notice it. oh yes had my radiator tanks pulled and rodded to confirm plugged radiator...40% plugged.
#20
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Year: 1996
Model: Cherokee
Engine: 4.0 h.o.
i believe the computer controls the aux fan to turn on&off from readings from the coolant temp sender as well as the head pressure sender on a/c system. wiring issue between computer & relay?
sorry imissed that you already replaced radiator & clutch fan does the aux fan come on when a/c is on...does it cycle?
sorry imissed that you already replaced radiator & clutch fan does the aux fan come on when a/c is on...does it cycle?
Last edited by cherokee country; 01-31-2010 at 08:45 PM. Reason: addition
#21
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Year: 1999
Model: Cherokee
Engine: 4.0
My math may be off, so bare with me. That gauge goes from 100* to 260*, so each has mark is 40 degrees or so, right? So 3 hash marks ( 3/4 of the gauge) should be around 220 right? If the fan is supposed to kick on at 219* and off at 209*, are you sure it gets hot enough for the fan to kick on?
Just a thought. I'm no expert.
Just a thought. I'm no expert.
#22
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Year: 1993
Model: Cherokee
Engine: 4.0
Mine's doing the same thing too, but I haven't had the chance to even start trying to figure that out yet, hopefully next weekend, keep us updated...
#23
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Year: 1992
Model: Cherokee
Engine: 4.0
Stock aux fan is supposed to kick at 217ish (have you verified it is?)
HAve you ever thought about taking out the manual fan and putting in an electric?
If your stock electric fan is not kickin on at right temp maybe throw in a thermal switch (probably 195ish) and running it off of that?
just tring to through out some ideas if you cant get it figured out
HAve you ever thought about taking out the manual fan and putting in an electric?
If your stock electric fan is not kickin on at right temp maybe throw in a thermal switch (probably 195ish) and running it off of that?
just tring to through out some ideas if you cant get it figured out
#24
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Year: 1991
Engine: 4.0 I-6 H.O.
Stock aux fan is supposed to kick at 217ish (have you verified it is?)
HAve you ever thought about taking out the manual fan and putting in an electric?
If your stock electric fan is not kickin on at right temp maybe throw in a thermal switch (probably 195ish) and running it off of that?
just tring to through out some ideas if you cant get it figured out
HAve you ever thought about taking out the manual fan and putting in an electric?
If your stock electric fan is not kickin on at right temp maybe throw in a thermal switch (probably 195ish) and running it off of that?
just tring to through out some ideas if you cant get it figured out
I was thinking about putting a T fitting where the coolant temp sensor is, and putting a bleed valve on the other side of the T
#25
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Year: 1991
Engine: 4.0 I-6 H.O.
My math may be off, so bare with me. That gauge goes from 100* to 260*, so each has mark is 40 degrees or so, right? So 3 hash marks ( 3/4 of the gauge) should be around 220 right? If the fan is supposed to kick on at 219* and off at 209*, are you sure it gets hot enough for the fan to kick on?
Just a thought. I'm no expert.
Just a thought. I'm no expert.
#26
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Year: 1991
Engine: 4.0 I-6 H.O.
i believe the computer controls the aux fan to turn on&off from readings from the coolant temp sender as well as the head pressure sender on a/c system. wiring issue between computer & relay?
sorry imissed that you already replaced radiator & clutch fan does the aux fan come on when a/c is on...does it cycle?
sorry imissed that you already replaced radiator & clutch fan does the aux fan come on when a/c is on...does it cycle?
#27
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Year: 2000
Model: Cherokee
Engine: 4.0L
The Aux fan shouldnt be causing this inthe winter..Heck mine is unplugged right now...
One of two Things are not Flowing, Either the Air through the Rad, or the water through the motor !
As long as you are moving there will be enough airflow to keep her cool. I suspect something is restricting the water flow. You replaced the hose, did you use the correct hose? I have seen hoses that would collapse and shutoff the flow !
One of two Things are not Flowing, Either the Air through the Rad, or the water through the motor !
As long as you are moving there will be enough airflow to keep her cool. I suspect something is restricting the water flow. You replaced the hose, did you use the correct hose? I have seen hoses that would collapse and shutoff the flow !
#28
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Year: 1990
Model: Cherokee
Engine: 4.0
my '90 was doing something similar...my fan only kicked on when the a/c was on and it would still run hot in stop & go traffic so i installed a 180 thermo and wired my fan to kick on when my ignition is on. been running like a champ ever since. hasn't run hot yet
#29
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Year: 1991
Model: Cherokee
Engine: 4.0
In 2005, my 91 overheated on a trip to Oklahoma from TN. My brother had owned the car since new and I had just got it. I ran the heater in a hot October to keep it from damaging anything. After looking over everything, I guessed that the radiator was undersized. It had been replaced 2 years earlier. I purchased a radiator with larger capacity, I can't remember from and to, and it solved my problem.
#30
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Year: 1991
Engine: 4.0 I-6 H.O.
Last night I tore it down, and took out the t-stat, then replaced the temp sensor with a new one, and put it back together.
After all that it was running at the 1/4 hash mark, I let it idle parked in front of my place for 30 minutes, then I drove it to walmart and then around a little and it never got much over the 1/4 hash mark, in fact some times when I got out in the open it would drop a little below the 1/4 hash, so I am pretty sure it was the t-stat, and when I was filling it I was squeezing the hoses and some big bubbles came out of the tee I installed in the heater line to flush the system
So I am gonna try and drive it some more maybe do some wheeling this weekend and see how she does. if it still stays cool, I am gonna put a superstant t-stat in there and see how it goes
After all that it was running at the 1/4 hash mark, I let it idle parked in front of my place for 30 minutes, then I drove it to walmart and then around a little and it never got much over the 1/4 hash mark, in fact some times when I got out in the open it would drop a little below the 1/4 hash, so I am pretty sure it was the t-stat, and when I was filling it I was squeezing the hoses and some big bubbles came out of the tee I installed in the heater line to flush the system
So I am gonna try and drive it some more maybe do some wheeling this weekend and see how she does. if it still stays cool, I am gonna put a superstant t-stat in there and see how it goes