clutch and electrical fan
#1
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Model: Cherokee (XJ)
clutch and electrical fan
I am not sure how normal it is to have both, on all these radiator removal videos the people just have an electrical fan. I have both a clutch fan and electrical fan.
???
???
#2
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Year: 1989 Laredo
Model: Cherokee
Engine: 4.0 L 6 Renix
On your XJ yes, that is normal, the electrical is an auxiliary and will come on/off at higher temps.
The XJ rad is short but wide.
The two fans cover the available area overall.
If you do off road water deep water crossing, consider changing out the clutch fan for a second elec. fan, switchable from in the cab.
If you won't be going in deep, then stock is great.
Watch older clutch fans for failure, can cause a big vibration.
Insure your fan shroud is secure, tendency for the screws to loosen.
The XJ rad is short but wide.
The two fans cover the available area overall.
If you do off road water deep water crossing, consider changing out the clutch fan for a second elec. fan, switchable from in the cab.
If you won't be going in deep, then stock is great.
Watch older clutch fans for failure, can cause a big vibration.
Insure your fan shroud is secure, tendency for the screws to loosen.
#3
CF Veteran
If your going through deep water a lot then you would want to keep the clutch fan. Water can short out an electric fan motor.
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Year: 1995
Model: Grand Cherokee (ZJ)
Engine: 4.0L
My ZJ 4.0L has a single viscous fan for it's downlfow radiator. The XJ's cross flow radiator normally requires a second (aux) fan, that comes on when conditions such as AC turned on, towing, road conditions change, such as steep grade, heavy sand, running constantly at lower rpms while off road, etc.
I prefer downflow rads as the crossflows imo are more sensitive and often run hotter when conditions change. My experience with the XJ crossflow it becomes sensitive to changes in drops in cooling system pressure. All rads require high pressure to keep the coolant at lower temp and preventing from boiling but imo the XJ crossflow is more sensitive than a downflow rad or at least ones I've used in the past.
The XJ with 4.0L coolant capacity is ~10.5 quarts (crossflow) and the ZJ with a 4.0L (downflow) is 12 quarts. Uses 1.5 quarts more coolant and only require a single viscous fan under all conditions. Some people modify the ZJ 4.0L fan from stock for more extreme conditions similar to the XJ 4.0L. But for general non extreme on and off road conditions the stock fans are usually adequate.
One modification for the XJ is to add a manual override switch to turn on and off the aux. fan instead of the allowing the PCM control the aux. fan from permanent temperature setpoints. On my 98 XJ 4.0L the pcm turns on the aux fan when the ac is running and also when the coolant temperature reaches 217 deg. F. the pcm then turns it off when coolant Temp. reaches 210 deg. F. The problem with PCM aux fan control is the PCM isn't able to predict road conditions and the fan turning on a 217 deg. F the engine ends up generally running at higher temperature and usually when at higher Temps 217 deg. F and higher when the engine is turned off engine / coolant Temps skyrocket and may take around 30 mins or so to cool off.
With a manual over-ride switch the driver, able to predict road conditions, can turn on the aux fan at around ~210 deg. F or less. so the engine runs generally cooler. With the manual over-ride switch I'm usually able to keep engine Temps at around
~210 deg. possibly less when in heavy sand, steep grades, towing, etc.
I prefer downflow rads as the crossflows imo are more sensitive and often run hotter when conditions change. My experience with the XJ crossflow it becomes sensitive to changes in drops in cooling system pressure. All rads require high pressure to keep the coolant at lower temp and preventing from boiling but imo the XJ crossflow is more sensitive than a downflow rad or at least ones I've used in the past.
The XJ with 4.0L coolant capacity is ~10.5 quarts (crossflow) and the ZJ with a 4.0L (downflow) is 12 quarts. Uses 1.5 quarts more coolant and only require a single viscous fan under all conditions. Some people modify the ZJ 4.0L fan from stock for more extreme conditions similar to the XJ 4.0L. But for general non extreme on and off road conditions the stock fans are usually adequate.
One modification for the XJ is to add a manual override switch to turn on and off the aux. fan instead of the allowing the PCM control the aux. fan from permanent temperature setpoints. On my 98 XJ 4.0L the pcm turns on the aux fan when the ac is running and also when the coolant temperature reaches 217 deg. F. the pcm then turns it off when coolant Temp. reaches 210 deg. F. The problem with PCM aux fan control is the PCM isn't able to predict road conditions and the fan turning on a 217 deg. F the engine ends up generally running at higher temperature and usually when at higher Temps 217 deg. F and higher when the engine is turned off engine / coolant Temps skyrocket and may take around 30 mins or so to cool off.
With a manual over-ride switch the driver, able to predict road conditions, can turn on the aux fan at around ~210 deg. F or less. so the engine runs generally cooler. With the manual over-ride switch I'm usually able to keep engine Temps at around
~210 deg. possibly less when in heavy sand, steep grades, towing, etc.
Last edited by Muddz; 01-29-2019 at 09:41 AM.
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