Sep 21, 2015, 03:49 PM
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XJ Ask the Question Thread
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
It's not a circle, but oblong. Has screw holes and tapered edges.
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
I have my new to me 1991 Cherokee 4.0. It has about 120k miles on it now, I got it with 118k. It looked like the waterpump and thermostat had been replaced. I flushed the coolant out about a week after buying it with 50/50. I took it on a few trips and it overheated, the idiot light didn't come on of course. I swapped gauge clusters with a new sending unit for the temperature. Now I can see it slowly overheat over time, as you can see in my avatar. I pulled the thermostat out today, it was a 160* failsafe in good condition, it was locked into the open position from all of the overheating. I removed the thermostat and refilled the system, its still appearing to overheat, 30 minutes of driving and already at 210*, I put some CLR to try and flush out the original metal radiator, I'll flush it out tomorrow and hopefully its just a clogged radiator.
Anybody have any advice what cured their over heating?
Anybody have any advice what cured their over heating?
CF Veteran
Joined: Apr 2014
Posts: 1,028
Likes: 0
From: Hagerstown MD
Year: 93
Model: Cherokee
Engine: 4.0 I6 w/Flux Capacitor
I have my new to me 1991 Cherokee 4.0. It has about 120k miles on it now, I got it with 118k. It looked like the waterpump and thermostat had been replaced. I flushed the coolant out about a week after buying it with 50/50. I took it on a few trips and it overheated, the idiot light didn't come on of course. I swapped gauge clusters with a new sending unit for the temperature. Now I can see it slowly overheat over time, as you can see in my avatar. I pulled the thermostat out today, it was a 160* failsafe in good condition, it was locked into the open position from all of the overheating. I removed the thermostat and refilled the system, its still appearing to overheat, 30 minutes of driving and already at 210*, I put some CLR to try and flush out the original metal radiator, I'll flush it out tomorrow and hopefully its just a clogged radiator.
Anybody have any advice what cured their over heating?
Anybody have any advice what cured their over heating?
Did ya burp it?
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
The open system is self burping and here is an excerpt from the Renix service manual regarding "burping" that system.
Check this out from the FSM
This system does not have a radiator pressure cap. Instead the pressure cap is mounted on the coolant pressure bottle. System coolant flows directly through a fully pressurized Hot-Type expansion bottle. Coolant flows through the pressure bottle at all times during engine operation whether the engine is cold or at normal operating temperatures.
Larger coolant volume caused by thermal expansion during engine operation is absorbed by the expansion chamber in the bottle. Air trapped in the system is purged through the pressure cap vent valve during maximum coolant expansion..
Check this out from the FSM
This system does not have a radiator pressure cap. Instead the pressure cap is mounted on the coolant pressure bottle. System coolant flows directly through a fully pressurized Hot-Type expansion bottle. Coolant flows through the pressure bottle at all times during engine operation whether the engine is cold or at normal operating temperatures.
Larger coolant volume caused by thermal expansion during engine operation is absorbed by the expansion chamber in the bottle. Air trapped in the system is purged through the pressure cap vent valve during maximum coolant expansion..
Moderator of Jeeps
Joined: Jul 2011
Posts: 21,029
Likes: 3
From: Frederick, MD from Cleveland, OH
Year: 1993 YJ Wrangler
Engine: 4.0 I6
Cruiser, I believe that burping isn't necessary in the intended operation of the 4.0L.
However, my YJ had severe overheating problems after replacing the radiator until I burped the system.
ITTs_Cole's XJ was overheating until we burped the system.
It works.
However, my YJ had severe overheating problems after replacing the radiator until I burped the system.
ITTs_Cole's XJ was overheating until we burped the system.
It works.
Herp Derp Jerp
Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
lol
New to you 24 year old Heep with a 160 failsafe in it, just recently sold tells me the PO had overheating, knew nothing about automotive cooling systems whatsoever so dumped it.
Since the water pump's already been replaced and you flushed everything, next suspect is the fan clutch. Probably been the fan clutch the whole time...
New to you 24 year old Heep with a 160 failsafe in it, just recently sold tells me the PO had overheating, knew nothing about automotive cooling systems whatsoever so dumped it.
Since the water pump's already been replaced and you flushed everything, next suspect is the fan clutch. Probably been the fan clutch the whole time...
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Moderator of Jeeps
Joined: Jul 2011
Posts: 21,029
Likes: 3
From: Frederick, MD from Cleveland, OH
Year: 1993 YJ Wrangler
Engine: 4.0 I6
I'm not arguing about how it's designed; I'm disagreeing with you from my experience with the way it functions.
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Since the system is older, should it have uncontrollable farting?