running hot
02-19-2015, 10:41 PM
#1
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running hot
I have an 01 Grand Cherokee, 4.0, and 4x4. I have replaced the thermostat, the radiator, upper and lower hose, radiator cap, and a radiator fan relay. I have had it block/pressure checked and no leak was found. I've taken it to multiple shops but no mechanic has been able to diagnose the issue. An help would be greatly appreciated..
02-20-2015, 09:49 AM
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Year: 2000
Model: Cherokee(XJ)
Engine: Golen 4.6L
Did you replace the fan clutch? That would be my next step.
Mine was running hot in traffic, and I tried the fan clutch tests you see posted here periodically with inconclusive results. So I just said screw it and replaced the damned thing. Instant improvement. It hasn't run hot since.
Eight bolts. $35. Easy job.
Mine was running hot in traffic, and I tried the fan clutch tests you see posted here periodically with inconclusive results. So I just said screw it and replaced the damned thing. Instant improvement. It hasn't run hot since.
Eight bolts. $35. Easy job.
02-22-2015, 05:15 PM
#3
Old fart with a wrench
No engine driven fan on an '01 4.0. I would suspect the water pump. Is the electric fan turning on at 210*F?
02-28-2015, 03:40 PM
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The mechanic said the water pump was fine and i have not noticed any leaks underneath the vehicle. The fan clutch was replaced not too long ago as well. I'm running out of ideas.
03-01-2015, 05:18 PM
#5
Old fart with a wrench
You've replaced everything else, why not try a new water pump? Plastic impellers tend to shatter easily because of the close clearances inside. Buy a premium pump with a METAL impeller.
Previous experience with a '97 ZJ.
Previous experience with a '97 ZJ.
03-01-2015, 10:03 PM
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Year: 2001
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Engine: 4.0L I6 HO
Also OP, you say its running hot. Be specific. What temps. When does it happen. Coolant loss etc. give us a bit more detail. And how does the mechanic know you pump is fine. They don't always leak when they go bad. Mines just failed one day on my 01 a few years back. Never leaked. Apparently the blades shattered as mentioned above
03-02-2015, 09:15 AM
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Year: 1994
Model: Grand Cherokee
Engine: v8
I second the water pump.
Before I broke out the wrenches though, I would check the block temp against the gauge reading. Ie, one of those laser thermometers when it is at operating temp. I changed out my temp sending unit with one from Amazon and it reads 50 degrees hotter than the laser reads. My water isn't boiling either, so I believe the thermometer as I'm pretty sure that I would have some steam at 240 degrees.
Before I broke out the wrenches though, I would check the block temp against the gauge reading. Ie, one of those laser thermometers when it is at operating temp. I changed out my temp sending unit with one from Amazon and it reads 50 degrees hotter than the laser reads. My water isn't boiling either, so I believe the thermometer as I'm pretty sure that I would have some steam at 240 degrees.
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03-02-2015, 09:13 PM
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Year: 1994
Model: Grand Cherokee
Engine: v8
this is the one I took out today
My daughter's car was "running hot".
I asked her about the heater. "it hasn't worked for months".
I traded cars with her on the way home from work, and drove it to operating temp... no higher, on the way to the hacienda.
It think a little JB weld and some Permatex will get me till next payday... What'choo think?
I asked her about the heater. "it hasn't worked for months".
I traded cars with her on the way home from work, and drove it to operating temp... no higher, on the way to the hacienda.
It think a little JB weld and some Permatex will get me till next payday... What'choo think?
03-02-2015, 09:15 PM
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Year: 2000
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A 50-50 mix of coolant has a boiling point of 223° F at sea level. A 12-lb cap should theoretically increase that by 36° to 259° F. A 16-lb cap should take you all the way up to 271°. Theoretically, of course.
Your system definitely should not boil at 240°. If it does, it has a problem.
03-02-2015, 09:33 PM
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Year: 1994
Model: Grand Cherokee
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Not necessarily. Remember that the system is under pressure, and the pressure is determined by your radiator cap (assuming that it's working properly). IIRC, for every degree F you increase the pressure, you also increase the boiling point by 3° F.
A 50-50 mix of coolant has a boiling point of 223° F at sea level. A 12-lb cap should theoretically increase that by 36° to 259° F. A 16-lb cap should take you all the way up to 271°. Theoretically, of course.
Your system definitely should not boil at 240°. If it does, it has a problem.
A 50-50 mix of coolant has a boiling point of 223° F at sea level. A 12-lb cap should theoretically increase that by 36° to 259° F. A 16-lb cap should take you all the way up to 271°. Theoretically, of course.
Your system definitely should not boil at 240°. If it does, it has a problem.
Let's try and help the guy with the problem and not play "Bill Nye" with the guy who doesn't have a problem (me), Okay?
03-03-2015, 05:05 PM
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Old fart with a wrench
03-04-2015, 09:07 AM
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Year: 1994
Model: Grand Cherokee
Engine: v8