Overheating insanity
CF Veteran
Joined: Jun 2011
Posts: 2,858
Likes: 1
From: Nor-Cal
Year: 1990
Model: Cherokee
Engine: The venerable 4.0
Originally Posted by djb383
I believe a properly functioningt t-stat will open in air or liquid....tested one on the center rack of the oven, it opened in air just like it did when in a pan of water.
Newbie
Joined: Aug 2011
Posts: 5
Likes: 0
Originally Posted by Roeboat
I have a 96 Cherokee Sport 4.0 and I am dealing with overheating issues. It overheats while driving or at idle, on cold days and on hot days.
Heater works fine. Fluid levels are good, and there is no leaking. There is def no oil in the coolant and exhaust is normal and def no white smoke. Reservoir is full with no leaks. There are no other fluid leaks of any kind. Head looks good. It starts great and runs great, without stalling or misfiring... it just over heats. It gets up to about 250's but I turn it off before it climbs any higher and I haven't let it get into the "red".
Things I have replaced...
-Radiator
-Water Pump
-Thermostat (and yes it was placed in the right direction)
-Fan shroud (grasping at straws!)
-Clutch Fan
-All temp sensors and fan related fuses
-Radiator Cap
-Serp Belt (and yes the pattern is correct)
Things I have done to it...
-Flushed the system multiple times including twice professionally flushed.
-Cleared air out of system
-Removed AC condenser to improve airflow to Radiator
My thoughts....
I am not impressed with the flow through the top Rad hose running from the thermostat housing. I have replaced the thermostat three times and confirmed it to be working in hot water with external temp gauge and it opens at about 200F (its 195F rated). Water pump has been confirmed to be the right one and it is moving in the right direction. Serp belt is DEF on right so its not that. Aux fan works when it is unplugged, but it wont come on when plugged in due to the sensor not receiving the hot fluid flow into the thermostat housing. But even if I start from a cold start, and have the Aux fan on the whole time (with it unplugged so it works) it still overheats.
Could there be some kind of other restriction preventing the coolant from either reaching the thermostat or preventing enough flow through it? Ive pawed around past the thermostat as much as I can, but could there be a restriction deeper in the engine block?
I have had all the freeze plugs replaced professionally. But now I wonder if an old freeze plug got pushed in and is causing restriction. Ive spoke with a few mechanics about that idea, but they all stated that it wouldn't restrict enough flow to cause a problem.
So, if it is indeed a fluid flow problem (which it might not be) and the thermostat is working then what could be causing that restriction?
Heater works fine. Fluid levels are good, and there is no leaking. There is def no oil in the coolant and exhaust is normal and def no white smoke. Reservoir is full with no leaks. There are no other fluid leaks of any kind. Head looks good. It starts great and runs great, without stalling or misfiring... it just over heats. It gets up to about 250's but I turn it off before it climbs any higher and I haven't let it get into the "red".
Things I have replaced...
-Radiator
-Water Pump
-Thermostat (and yes it was placed in the right direction)
-Fan shroud (grasping at straws!)
-Clutch Fan
-All temp sensors and fan related fuses
-Radiator Cap
-Serp Belt (and yes the pattern is correct)
Things I have done to it...
-Flushed the system multiple times including twice professionally flushed.
-Cleared air out of system
-Removed AC condenser to improve airflow to Radiator
My thoughts....
I am not impressed with the flow through the top Rad hose running from the thermostat housing. I have replaced the thermostat three times and confirmed it to be working in hot water with external temp gauge and it opens at about 200F (its 195F rated). Water pump has been confirmed to be the right one and it is moving in the right direction. Serp belt is DEF on right so its not that. Aux fan works when it is unplugged, but it wont come on when plugged in due to the sensor not receiving the hot fluid flow into the thermostat housing. But even if I start from a cold start, and have the Aux fan on the whole time (with it unplugged so it works) it still overheats.
Could there be some kind of other restriction preventing the coolant from either reaching the thermostat or preventing enough flow through it? Ive pawed around past the thermostat as much as I can, but could there be a restriction deeper in the engine block?
I have had all the freeze plugs replaced professionally. But now I wonder if an old freeze plug got pushed in and is causing restriction. Ive spoke with a few mechanics about that idea, but they all stated that it wouldn't restrict enough flow to cause a problem.
So, if it is indeed a fluid flow problem (which it might not be) and the thermostat is working then what could be causing that restriction?
Newbie
Joined: Aug 2011
Posts: 5
Likes: 0
Originally Posted by nitsche.6959
I replaced my radiator as well but in three days it went bad when I put in all copper one my problem was over
Newbie
Joined: Aug 2011
Posts: 5
Likes: 0
Originally Posted by Roeboat
I have a 96 Cherokee Sport 4.0 and I am dealing with overheating issues. It overheats while driving or at idle, on cold days and on hot days.
Heater works fine. Fluid levels are good, and there is no leaking. There is def no oil in the coolant and exhaust is normal and def no white smoke. Reservoir is full with no leaks. There are no other fluid leaks of any kind. Head looks good. It starts great and runs great, without stalling or misfiring... it just over heats. It gets up to about 250's but I turn it off before it climbs any higher and I haven't let it get into the "red".
Things I have replaced...
-Radiator
-Water Pump
-Thermostat (and yes it was placed in the right direction)
-Fan shroud (grasping at straws!)
-Clutch Fan
-All temp sensors and fan related fuses
-Radiator Cap
-Serp Belt (and yes the pattern is correct)
Things I have done to it...
-Flushed the system multiple times including twice professionally flushed.
-Cleared air out of system
-Removed AC condenser to improve airflow to Radiator
My thoughts....
I am not impressed with the flow through the top Rad hose running from the thermostat housing. I have replaced the thermostat three times and confirmed it to be working in hot water with external temp gauge and it opens at about 200F (its 195F rated). Water pump has been confirmed to be the right one and it is moving in the right direction. Serp belt is DEF on right so its not that. Aux fan works when it is unplugged, but it wont come on when plugged in due to the sensor not receiving the hot fluid flow into the thermostat housing. But even if I start from a cold start, and have the Aux fan on the whole time (with it unplugged so it works) it still overheats.
Could there be some kind of other restriction preventing the coolant from either reaching the thermostat or preventing enough flow through it? Ive pawed around past the thermostat as much as I can, but could there be a restriction deeper in the engine block?
I have had all the freeze plugs replaced professionally. But now I wonder if an old freeze plug got pushed in and is causing restriction. Ive spoke with a few mechanics about that idea, but they all stated that it wouldn't restrict enough flow to cause a problem.
So, if it is indeed a fluid flow problem (which it might not be) and the thermostat is working then what could be causing that restriction?
Heater works fine. Fluid levels are good, and there is no leaking. There is def no oil in the coolant and exhaust is normal and def no white smoke. Reservoir is full with no leaks. There are no other fluid leaks of any kind. Head looks good. It starts great and runs great, without stalling or misfiring... it just over heats. It gets up to about 250's but I turn it off before it climbs any higher and I haven't let it get into the "red".
Things I have replaced...
-Radiator
-Water Pump
-Thermostat (and yes it was placed in the right direction)
-Fan shroud (grasping at straws!)
-Clutch Fan
-All temp sensors and fan related fuses
-Radiator Cap
-Serp Belt (and yes the pattern is correct)
Things I have done to it...
-Flushed the system multiple times including twice professionally flushed.
-Cleared air out of system
-Removed AC condenser to improve airflow to Radiator
My thoughts....
I am not impressed with the flow through the top Rad hose running from the thermostat housing. I have replaced the thermostat three times and confirmed it to be working in hot water with external temp gauge and it opens at about 200F (its 195F rated). Water pump has been confirmed to be the right one and it is moving in the right direction. Serp belt is DEF on right so its not that. Aux fan works when it is unplugged, but it wont come on when plugged in due to the sensor not receiving the hot fluid flow into the thermostat housing. But even if I start from a cold start, and have the Aux fan on the whole time (with it unplugged so it works) it still overheats.
Could there be some kind of other restriction preventing the coolant from either reaching the thermostat or preventing enough flow through it? Ive pawed around past the thermostat as much as I can, but could there be a restriction deeper in the engine block?
I have had all the freeze plugs replaced professionally. But now I wonder if an old freeze plug got pushed in and is causing restriction. Ive spoke with a few mechanics about that idea, but they all stated that it wouldn't restrict enough flow to cause a problem.
So, if it is indeed a fluid flow problem (which it might not be) and the thermostat is working then what could be causing that restriction?
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Member
Joined: Dec 2009
Posts: 165
Likes: 0
Model: Cherokee
Have you recently had the head gasket replaced ? There is definitely something blocking the collant from being circulated properly in the block's water jackets.
A defective head gasket that does not have all the holes in the correct location is a possibility, although a rare event.
Frustrating, Yes ?
A defective head gasket that does not have all the holes in the correct location is a possibility, although a rare event.
Frustrating, Yes ?
Last edited by webb'scherokee; Aug 6, 2011 at 04:39 PM.
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
All I'm saying is, t-stat starts to open at it's rated temp whether it's in air or liquid.....any automotive cooling system needs to be filled slowly, with motor idling and rad cap off, to eliminate (burp) air in the system. Coolant should be circulating thru the block, then thru the head, then beside the t-stat and back to the water pump the moment the motor is started (hot or cold).
Last edited by djb383; Aug 6, 2011 at 05:11 PM.
Member
Joined: Jun 2011
Posts: 165
Likes: 0
From: Salamanca NY
Year: 2000
Model: Cherokee
Engine: 4.0 IL6
I had this problem once on my 95 Cherokee and found out the radiators are a little under sized and the aluminum radiator are **** to electrolysis do to electrical feed back and that if the water you put in has high mineral content u can clog up the tubes. I replaced my radiator with all copper one and proper water and every thing was fine
Member
Joined: Dec 2009
Posts: 165
Likes: 0
Model: Cherokee
The mineral content is disolved. However, if you are speaking of mineral sediment, then that is an entirely different and more serious situation. There are disolved minerals in socalled "city water", but definently no sediment, all of which is fitered out with EXTREMELY effective filter elements.
And yes, who operates their Jeeps with 100 per-cent water as their coolant ? No one that I know. Depending upon the winter temps in a given area, the norm would be a 50/50 mixture of water and anti-freeze, or better.
The poster has stated that he has a new radiator, and has flushed the entire system twice. Unless he was not present to witness the system flushing being done and the tech who was supposed to have done it is a liar, I have to believe that he has done what would be a normal proceedure to maintain an effective cooling system.
And yes, who operates their Jeeps with 100 per-cent water as their coolant ? No one that I know. Depending upon the winter temps in a given area, the norm would be a 50/50 mixture of water and anti-freeze, or better.
The poster has stated that he has a new radiator, and has flushed the entire system twice. Unless he was not present to witness the system flushing being done and the tech who was supposed to have done it is a liar, I have to believe that he has done what would be a normal proceedure to maintain an effective cooling system.