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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
Hi , my name is jaysen and I’ve had this XJ for 2 years now and it only has 171,000 miles I bought it at 159,000 .and untill a couple months ago I started to notice it running warmer and warmer untill eventually the smallest load on it such as a hill or going over about 55mph causes it to over heat. It’s boggeled me for months now. Before I bought the jeep the previous owner had switched to newer radiator and deleted the closed system with new hoses water pump and t-stat. Which worked great over the past two years infact my usual temps for the XJ have always been around 190-200 degrees even driving aggressively. The only thing that changed recently is I had my heater core start leaking so all I did was unplug it and loop the connections with a U joint and two connectors to connect the heater hose coming out of the thermostat and into the waterpump . Now when I first did this I only saw a small increase of temprature up to 205 . Which I was okay with . But recently when I get onto highway speeds of 55 and above . The temp moves rapidly slowing down at 210 and then slowly moving over to around 230 I always shut it off before it gets to the red as I don’t want to ruin my engine . So to try and combat this temp I’ve installed at 180 degree t-stat , flushes the radiator with red devil radiator flush and added a newer “high flowing” t-stat housing. I’ve been trying to do all I can to keep it under temps . My next step would be replacing the water pump . But it doesn’t show any signs of being broken, it doesn’t squeak or vibrate on the pully and I can’t move the pully back and fourth like that’s thats the problem . Or the radiator which I’ve made sure is clean and no veins are blocked and made sure it’s got 50/50 coolant in it. And it’s clean . Any help would be appreciated , I’ve made dumb mistakes before and would appreciate any guidance. This is my first car and I like learning about it and working on over the 2 years it’s taught me a lot and I’d hate for this to be the end if I can’t stop it from overheating. And another note I didn’t think of. It has and ac compressor but it never kicks on so that ist putting a load on it either . The fan clutch is good and the electric fan comes on around 180 degrees and seems to function fine. . Thank you for reading this if you have any questions let me know or if I didn’t explain something well enough I’ll try and explain better haha ! Pic included just to show what my Jeep looks like
Hi, my name is Jayson and I’ve had this XJ for 2 years now and it only has 171,000 miles. I bought it at 159,000 .and until a couple of months ago I started to notice it running warmer and warmer until eventually the smallest load on it such as a hill or going over about 55mph causes it to overheat. It’s boggled me for months now. Before I bought the jeep the previous owner had switched to a newer radiator and deleted the closed system with new hoses water pump and t-stat. Which worked great over the past two years in fact my usual temps for the XJ have always been around 190-200 degrees even driving aggressively.
The only thing that changed recently is I had my heater core start leaking so all I did was unplug it and loop the connections with a U joint and two connectors to connect the heater hose coming out of the thermostat and into the water pump. Now when I first did this I only saw a small increase in temperature up to 205. Which I was okay with. But recently when I get onto highway speeds of 55 and above. The temp moves rapidly slowing down at 210 and then slowly moving over to around 230. I always shut it off before it gets to the red as I don’t want to ruin my engine.
So to try and combat this temp I’ve installed at 180-degree t-stat, flushes the radiator with a red devil radiator flush, and added a newer “high flowing” t-stat housing. I’ve been trying to do all I can to keep it under temps. My next step would be replacing the water pump. But it doesn’t show any signs of being broken, it doesn’t squeak or vibrate on the pully and I can’t move the pully back and forth like that’s the problem. Or the radiator which I’ve made sure is clean and no veins are blocked and made sure it’s got 50/50 coolant in it. And it’s clean.
Any help would be appreciated, I’ve made dumb mistakes before and would appreciate any guidance. This is my first car and I like learning about it and working on over the 2 years it’s taught me a lot and I’d hate for this to be the end if I can’t stop it from overheating. And another note I didn’t think of. It has an ac compressor but it never kicks on so that ist putting a load on it either. The fan clutch is good and the electric fan comes on around 180 degrees and seems to function fine. Thank you for reading this if you have any questions let me know or if I didn’t explain something well enough I’ll try and explain better haha! Pic included just to show what my Jeep looks like
Check the fan clutch , if it's not locking up the way it should you will over heat .
If it's only overheating at highway speeds, the fan clutch (or e-fan, for that matter) should be irrelevant. Sounds to me like there's a coolant flow or airflow problem, or the radiator is clogged. I'm guessing the thermostat isn't opening all the way. Since the water pump is relatively new, the impeller should be fine. If the thermostat isn't faulty, then the only other cause would be gunk inside the radiator blocking the coolant flow.
You could try pulling the thermostat and running it on the highway to see it that helps.
After disconnecting and bypassing your heater core, air may have become trapped in the system which could cause a loss of coolant flow and be a reason for your overheating issue.
When flushing the coolant system, If you did not burp your XJ, once again air can be trapped causing you to overheat.
Just a thought, Good luck!
Hi, my name is Jayson and I’ve had this XJ for 2 years now and it only has 171,000 miles. I bought it at 159,000 .and until a couple of months ago I started to notice it running warmer and warmer until eventually the smallest load on it such as a hill or going over about 55mph causes it to overheat. It’s boggled me for months now. Before I bought the jeep the previous owner had switched to a newer radiator and deleted the closed system with new hoses water pump and t-stat. Which worked great over the past two years in fact my usual temps for the XJ have always been around 190-200 degrees even driving aggressively.
The only thing that changed recently is I had my heater core start leaking so all I did was unplug it and loop the connections with a U joint and two connectors to connect the heater hose coming out of the thermostat and into the water pump. Now when I first did this I only saw a small increase in temperature up to 205. Which I was okay with. But recently when I get onto highway speeds of 55 and above. The temp moves rapidly slowing down at 210 and then slowly moving over to around 230. I always shut it off before it gets to the red as I don’t want to ruin my engine.
So to try and combat this temp I’ve installed at 180-degree t-stat, flushes the radiator with a red devil radiator flush, and added a newer “high flowing” t-stat housing. I’ve been trying to do all I can to keep it under temps. My next step would be replacing the water pump. But it doesn’t show any signs of being broken, it doesn’t squeak or vibrate on the pully and I can’t move the pully back and forth like that’s the problem. Or the radiator which I’ve made sure is clean and no veins are blocked and made sure it’s got 50/50 coolant in it. And it’s clean.
Any help would be appreciated, I’ve made dumb mistakes before and would appreciate any guidance. This is my first car and I like learning about it and working on over the 2 years it’s taught me a lot and I’d hate for this to be the end if I can’t stop it from overheating. And another note I didn’t think of. It has an ac compressor but it never kicks on so that ist putting a load on it either. The fan clutch is good and the electric fan comes on around 180 degrees and seems to function fine. Thank you for reading this if you have any questions let me know or if I didn’t explain something well enough I’ll try and explain better haha! Pic included just to show what my Jeep looks like
ftfy
I appreciate the fix but my name is spelled "Jaysen" haha . But seriously thank you, like I said I had written this post on a phone which did not help my grammar.
After disconnecting and bypassing your heater core, air may have become trapped in the system which could cause a loss of coolant flow and be a reason for your overheating issue.
When flushing the coolant system, If you did not burp your XJ, once again air can be trapped causing you to overheat.
Just a thought, Good luck!
Sounds like a good idea I will try that Tuesday when i have time to work on it. Ill burp it and check my fan clutch, and then get back to this post and ill do my best to grab pictures .
Really? Where's the coolant going to go with the thermostat closed?
It doesn't need to go anywhere. Coolant goes from the thermostat housing before the thermostat, through the heater core and returns into the water pump. The heater core normally limits that flow, but I suspect just connecting the hoses together is allowing a lot more to flow that path instead of going through the radiator. You could also connect them with a smaller connector to restrict the flow. Also, a hi-flow pump and hi-flow thermostat housing have actually been know to cause more overheating.
Overheating at highway speeds is typically a water flow issue.
Basic cooling system trouble shooting
Idle or low speed- airflow issue
Bad E fan
Bad fan clutch
clogged radiator fins
stuff like that.
Overheating at speed - waterflow issue
Clogged radiator core(tubes), you can sometimes check this using an IR temperature gun and checking various points of the radiator. When they get clogged with sediment they typically clog from the bottom up on a cross flow radiator like ours. If you see "cold" spots on the radiator you are probably seeing a clog since no coolant is flowing though that spot.
Bad water pump
too much junk in the block
This is just a generality there are things that can cause overheating in both situations but if your overheating is limited to one of those two things then it's typically caused by one of those issues
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Originally Posted by IJM
If it's only overheating at highway speeds, the fan clutch (or e-fan, for that matter) should be irrelevant. Sounds to me like there's a coolant flow or airflow problem, or the radiator is clogged. I'm guessing the thermostat isn't opening all the way. Since the water pump is relatively new, the impeller should be fine. If the thermostat isn't faulty, then the only other cause would be gunk inside the radiator blocking the coolant flow.
You could try pulling the thermostat and running it on the highway to see it that helps.
06-28-2020, 05:02 PM
87 Jeep XJ overheating when at highway speeds
