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Jeep not cooling like it used to

IslanderOffRoad

IslanderOffRoad

NAXJA Forum User
NAXJA Member
Location
Houston, Tx
In July, I had my fan go through my radiator.

Since then I've replaced:

Radiator 3-core CSF
Motor Mounts (MORE Bombproof)
Fan Shroud

I had a slight leak at the heater valve so I replaced that as well. My fan and clutch appeared to be ok so I did not replace them.

I've noticed lately that the Jeep heats up a bit more at extended idling than it used to, creeps up above 210 a bit. I've got no a/c so I unplugged the compressor, and turning on the a/c turns on my aux fan, this will get the temp back down. After extended periods of freeway speed the needle again creeps a bit above 210. A downhill stretch with less load on the engine cools it right back down.

Running a 50/50 coolant/water mix with one bottle of Red Liner Water Wetter.

So what is this a symptom of?

Seems like the fan/clutch would explain the idle issue but shouldn't make a difference at the higher speeds

Water pump has never had issues, thermostat was replaced in september of last year.

Any advice is appreciated, I hate cooling systems.
 
you're probably correct in thinking that a malfunctioning fan clutch may affect cooling at idle... however... if the fan clutch is capable of operating properly, it will only do so in response to coolant flowing through the radiator directly in front of it. the second symptom you mention regarding increasing temperatures at highway speed suggests a lack of flow, either through, or to, the radiator.
given both symptoms, I'd be inclined to replace the thermostat first, even if it was replaced last September. If the thermostat goes through an "incident" such as rapid coolant loss, or moreso... overheating, it can render it inoperative, or partially operational.

Recommend: replace thermostat, refill system with correct mixture of coolant and water, and re-evaluate following repair.
 
A 3 core radiator may have contributed also. The thicker core makes it more difficult for the air to move through it. Most newer high efficency cores are 2 at most. Given the XJ fans inability to move air, it may have been a move in the wrong direction.
 
If it's just going a few deg's over 210 I would leave it alone. After the rad problem you may be watching your gauge closer and maybe a little to close. IF NOT
I didn't see the year of the XJ but if it's a closed system? After replacing t-stat insure it is properly purged of air. If the idle problem then persist replace fan. Then a compression check.
Last word " Red Liner Water Wetter" waste of time and money for a DD.
 
Jay VT said:
A 3 core radiator may have contributed also. The thicker core makes it more difficult for the air to move through it. Most newer high efficency cores are 2 at most. Given the XJ fans inability to move air, it may have been a move in the wrong direction.
Click to expand...

Doubtful, I had a 3-core in it before, so that shouldn't have made a difference.
 
badron said:
If it's just going a few deg's over 210 I would leave it alone. After the rad problem you may be watching your gauge closer and maybe a little to close. IF NOT
I didn't see the year of the XJ but if it's a closed system? After replacing t-stat insure it is properly purged of air. If the idle problem then persist replace fan. Then a compression check.
Last word " Red Liner Water Wetter" waste of time and money for a DD.
Click to expand...

94

Red line did seem to help me drop a few degrees, its worth a couple bucks IMO.
 
IslanderOffRoad said:
In July, I had my fan go through my radiator.

Since then I've replaced:

Radiator 3-core CSF
Motor Mounts (MORE Bombproof)
Fan Shroud

I had a slight leak at the heater valve so I replaced that as well. My fan and clutch appeared to be ok so I did not replace them.

I've noticed lately that the Jeep heats up a bit more at extended idling than it used to, creeps up above 210 a bit. I've got no a/c so I unplugged the compressor, and turning on the a/c turns on my aux fan, this will get the temp back down. After extended periods of freeway speed the needle again creeps a bit above 210. A downhill stretch with less load on the engine cools it right back down.

Running a 50/50 coolant/water mix with one bottle of Red Liner Water Wetter.

So what is this a symptom of?

Seems like the fan/clutch would explain the idle issue but shouldn't make a difference at the higher speeds

Water pump has never had issues, thermostat was replaced in september of last year.

Any advice is appreciated, I hate cooling systems.
Click to expand...


Cause it's been a 100 freakin' + degrees out in the valley.

Sounds like normal operation to me.
 
karstic said:
Cause it's been a 100 freakin' + degrees out in the valley.

Sounds like normal operation to me.
Click to expand...

I suppose that could be it, but even when I'm down in west LA where its 20 degrees cooler its not as efficent as it used to be.
 
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