Odd overheating issue
06-13-2017, 01:02 PM
#1
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0L 6cyl
Odd overheating issue
Ok , This is new.
So my 1992 xj is running excellent. I replaced the oil pump and am getting good oil pressure, there are no knocks, Idle is good, and it successfully put 1/3 of a container of sea foam through the cylinders. It smokes barely when idling at a light and it doesn't plume when accelerating. Runs at 210-220 when fully heated with a 160 thermostat. The issue is when I turn the engine off.
After sitting for a minute or two with the engine off and the key in the ignition (to watch the temperature meter) it rises to the 3/4 temperatures marker and sometimes comes out of the overflow tank. Has done this for quite a while as it initially was getting hot while running. After replacing the oil pump, it runs great, it just doesn't cool after sitting. Please tell me if this isn't clear, Im writing this rather fast.
So my 1992 xj is running excellent. I replaced the oil pump and am getting good oil pressure, there are no knocks, Idle is good, and it successfully put 1/3 of a container of sea foam through the cylinders. It smokes barely when idling at a light and it doesn't plume when accelerating. Runs at 210-220 when fully heated with a 160 thermostat. The issue is when I turn the engine off.
After sitting for a minute or two with the engine off and the key in the ignition (to watch the temperature meter) it rises to the 3/4 temperatures marker and sometimes comes out of the overflow tank. Has done this for quite a while as it initially was getting hot while running. After replacing the oil pump, it runs great, it just doesn't cool after sitting. Please tell me if this isn't clear, Im writing this rather fast.
06-13-2017, 03:20 PM
#4
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Year: 1996
Model: Cherokee
Engine: 4.0
Ya, really should be a 195*
What does it do if you run to operating temp then allow to idle? Does it still spike and boil over? Have you done any other maintenance to the cooling system other than the stat?
What does it do if you run to operating temp then allow to idle? Does it still spike and boil over? Have you done any other maintenance to the cooling system other than the stat?
06-13-2017, 03:24 PM
#5
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fwiw all vehicles will heat up the first few minutes after you turn them off.....but it does sound like you have an issue, it should not be boiling out. I'm guessing you temperature gauge/temp sending unit is not working properly--check the temps with an IR thermometer while it's running.
06-13-2017, 03:26 PM
#6
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0L 6cyl
I have not done anything other than a coolant flush and a stat.
06-13-2017, 03:30 PM
#7
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0L 6cyl
fwiw all vehicles will heat up the first few minutes after you turn them off.....but it does sound like you have an issue, it should not be boiling out. I'm guessing you temperature gauge/temp sending unit is not working properly--check the temps with an IR thermometer while it's running.
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06-13-2017, 05:23 PM
#14
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Year: 2001
Model: Cherokee
Engine: 4.0 Litre I6
My theory, may be wrong. But I'm going to give it shot.
If the radiator is indeed painted, it's cooling factor is no doubt compromised. Everything is fine and dandy with the mech or e-fan blowing.
Once the key is turned off, because of physics, the coolant will still continue to slowly flow around the loop, dissipating heat at the radiator.
In OPs XJ, the coolant is obviously still flowing after the key is turned off. However, the radiators cooling factor is compromised and can not cool the coolant sufficiently without being aided by air flow.
What do ya'll think?
If the radiator is indeed painted, it's cooling factor is no doubt compromised. Everything is fine and dandy with the mech or e-fan blowing.
Once the key is turned off, because of physics, the coolant will still continue to slowly flow around the loop, dissipating heat at the radiator.
In OPs XJ, the coolant is obviously still flowing after the key is turned off. However, the radiators cooling factor is compromised and can not cool the coolant sufficiently without being aided by air flow.
What do ya'll think?
06-13-2017, 05:23 PM
#15
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