87 Jeep XJ overheating when at highway speeds
#16
Seasoned Member
I've had this problem before. Probably a clogged radiator, and/or fan clutch. make sure that your fan shroud is good as well. Make sure the coolant mixture is correct, and use distilled water. Too much glycol does not cool. Use a new Stant 190* thermostat.
#17
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Year: 1987
Model: Cherokee (XJ)
Engine: 4.0
Hey its me again! , here is an update and some pictures I took today while working on the Heep. So I was able to flush the radiator and the block with a garden hose, both came out clear and do not show any signs of blockage. The only possible issue i found was the return line from the thermostat back to the water pump. it was grimy and dirty but not clogged . I even flushed with water , but the same result the water was clear and no particulates. Next I removed the grill insert and was able to blast some water through the radiator to make sure it wasn't dirty. Pictures of the radiator are below along with the return line to the water pump being grimy. lastly I refilled the radiator with coolant and some "Royal Purple Ice Super coolant" which is suppose to slow down the how fast the coolant heats up (if that makes any sense). i burped the system by opening the "plug" I have in the thermostat housing and running the jeep in the drive way with the radiator cap off to let any air out for about 5 minutes. in newer Cherokees that plug is for a temperature sensor but because mine is an 87 i do not have that sensor. So i simply put a plug, and the plug is not long and extends into the thermostat housing. it only extends maybe half a centimetre into the housing so it does not block flow.
I Apologize if the grammar or sentencing is off I tried to proof read it before i submitted it. And once again I am a newbie and just wanting to learn and fix things myself than rather going to a shop. I was able to drive to the gas station and back, the two thing i noticed was my temp was at about 150 degrees when i shut it off to pump gas for less than 5 minutes and when i turned it back on the temp gauge was at about 200 Degrees. Once i got back on the road to drive home it did cool back down to about 190 when i was driving. But once i parked it and let it run it heated back up to temp. And when i was checking the radiator when i parked it the e-fan was on and i could feel it pull way more air than the fan on the engine. And i also was driving with the grill off to maximize airflow if that helps at all.
This is the grimy hose leading to the water pump from the thermostat
here is the Thermostat housing with the plug shown on the right side
I Apologize if the grammar or sentencing is off I tried to proof read it before i submitted it. And once again I am a newbie and just wanting to learn and fix things myself than rather going to a shop. I was able to drive to the gas station and back, the two thing i noticed was my temp was at about 150 degrees when i shut it off to pump gas for less than 5 minutes and when i turned it back on the temp gauge was at about 200 Degrees. Once i got back on the road to drive home it did cool back down to about 190 when i was driving. But once i parked it and let it run it heated back up to temp. And when i was checking the radiator when i parked it the e-fan was on and i could feel it pull way more air than the fan on the engine. And i also was driving with the grill off to maximize airflow if that helps at all.
This is the grimy hose leading to the water pump from the thermostat
here is the Thermostat housing with the plug shown on the right side
#19
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I've had over heating at highway speeds as well, actually a couple different. The first time it was a clogged radiator and the second time my lower radiator hose was collapsing on its self.
#22
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Year: 1987
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that is the AC condenser. And believe it or not I wish one day to get the AC fixed other wise id have taken it out lol
#23
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I think you could be bypassing to much coolant though the heater hoses , if you had a heater core hooked up it would slow down the coolant that would be going though the heater hoses .maybe you can pinch off some of the heater hose to stop the coolant from bypassing the radiator .
#24
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Year: 1987
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I think you could be bypassing to much coolant though the heater hoses , if you had a heater core hooked up it would slow down the coolant that would be going though the heater hoses .maybe you can pinch off some of the heater hose to stop the coolant from bypassing the radiator .
that sounds like a good idea , after I did the flush and etc when I posted the pictures it only seemed to help slow down how fast it was getting to temp . Could I also shorten the heater house to slow the flow down ?
#25
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Shortening the heater hose would increase flow through the heater hose, no? If anything, you'd want to restrict the flow through that circuit to force more coolant through the radiator.
#26
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Year: 1998 Classic (I'll get it running soon....) and 02 Grand
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