Re: fluid drive cooling fan
 

On Oct 18, 5:22 am, ncf...@yahoo.com wrote:
> 2001 GC Jeep 4.7,,,,cooling fan motor is fluid drive ,, from the power
> stearing unit. The fan drive is activated by what and where is it
> located??.
>
> Where or what sends the signal ??? located??
>
> The fan runs and will cool ,, but only when the temp guage goes over
> the half way mark .
>
> At this temp the jeep is starting to experenceing over heating
> problems.

This is an oil driven fan, on a PWM circuit, commanded by the PCM.

If the engine is overheating, the first thing you should do/have done
is a block check for combustion gases. I've done head gaskets on a
couple of these for this concern.

Good luck.

Re: fluid drive cooling fan
 

On Oct 18, 5:22 am, ncf...@yahoo.com wrote:
> 2001 GC Jeep 4.7,,,,cooling fan motor is fluid drive ,, from the power
> stearing unit. The fan drive is activated by what and where is it
> located??.
>
> Where or what sends the signal ??? located??
>
> The fan runs and will cool ,, but only when the temp guage goes over
> the half way mark .
>
> At this temp the jeep is starting to experenceing over heating
> problems.

This is an oil driven fan, on a PWM circuit, commanded by the PCM.

If the engine is overheating, the first thing you should do/have done
is a block check for combustion gases. I've done head gaskets on a
couple of these for this concern.

Good luck.

Re: fluid drive cooling fan
 

On Oct 18, 5:22 am, ncf...@yahoo.com wrote:
> 2001 GC Jeep 4.7,,,,cooling fan motor is fluid drive ,, from the power
> stearing unit. The fan drive is activated by what and where is it
> located??.
>
> Where or what sends the signal ??? located??
>
> The fan runs and will cool ,, but only when the temp guage goes over
> the half way mark .
>
> At this temp the jeep is starting to experenceing over heating
> problems.

This is an oil driven fan, on a PWM circuit, commanded by the PCM.

If the engine is overheating, the first thing you should do/have done
is a block check for combustion gases. I've done head gaskets on a
couple of these for this concern.

Good luck.

Re: fluid drive cooling fan
 

On cars that didn't change their coolant, hopefully.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

"juiceman" <juiceman5150@gmail.com> wrote in message
news:1192756499.336687.296200@k35g2000prh.googlegr oups.com...
>
> This is an oil driven fan, on a PWM circuit, commanded by the PCM.
>
> If the engine is overheating, the first thing you should do/have done
> is a block check for combustion gases. I've done head gaskets on a
> couple of these for this concern.
>
> Good luck.
>
>

Re: fluid drive cooling fan
 

On cars that didn't change their coolant, hopefully.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

"juiceman" <juiceman5150@gmail.com> wrote in message
news:1192756499.336687.296200@k35g2000prh.googlegr oups.com...
>
> This is an oil driven fan, on a PWM circuit, commanded by the PCM.
>
> If the engine is overheating, the first thing you should do/have done
> is a block check for combustion gases. I've done head gaskets on a
> couple of these for this concern.
>
> Good luck.
>
>

Re: fluid drive cooling fan
 

On cars that didn't change their coolant, hopefully.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

"juiceman" <juiceman5150@gmail.com> wrote in message
news:1192756499.336687.296200@k35g2000prh.googlegr oups.com...
>
> This is an oil driven fan, on a PWM circuit, commanded by the PCM.
>
> If the engine is overheating, the first thing you should do/have done
> is a block check for combustion gases. I've done head gaskets on a
> couple of these for this concern.
>
> Good luck.
>
>

Re: fluid drive cooling fan
 

"juiceman" <juiceman5150@gmail.com> wrote in message
news:1192756499.336687.296200@k35g2000prh.googlegr oups.com...
>
> This is an oil driven fan, on a PWM circuit, commanded by the PCM.
>

Could you give us the Reader's Digest description of what you just said.

I'm not familiar with an "oil driven fan," and the part about the PWM
circuit has me scratching my head.

Re: fluid drive cooling fan
 

"juiceman" <juiceman5150@gmail.com> wrote in message
news:1192756499.336687.296200@k35g2000prh.googlegr oups.com...
>
> This is an oil driven fan, on a PWM circuit, commanded by the PCM.
>

Could you give us the Reader's Digest description of what you just said.

I'm not familiar with an "oil driven fan," and the part about the PWM
circuit has me scratching my head.

Re: fluid drive cooling fan
 

"juiceman" <juiceman5150@gmail.com> wrote in message
news:1192756499.336687.296200@k35g2000prh.googlegr oups.com...
>
> This is an oil driven fan, on a PWM circuit, commanded by the PCM.
>

Could you give us the Reader's Digest description of what you just said.

I'm not familiar with an "oil driven fan," and the part about the PWM
circuit has me scratching my head.

Re: fluid drive cooling fan
 

On Thu, 18 Oct 2007 02:22:04 -0700, ncflnc@yahoo.com wrote:

>2001 GC Jeep 4.7,,,,cooling fan motor is fluid drive ,, from the power
>stearing unit. The fan drive is activated by what and where is it
>located??.
>
>Where or what sends the signal ??? located??
>
>The fan runs and will cool ,, but only when the temp guage goes over
>the half way mark .
>
>At this temp the jeep is starting to experenceing over heating
>problems.

WJ's w/4.7 V8's and WK 5.7 and Diesel use a Radiator Mounted Hydraulic
Powered Fan.

The Power Steering Pump has two rotors and two circuits, one dedicated
for the Fan and one for Power Steering.

The Hydraulic Fan is driven by a Gerotor type motor and there is a
solenoid on it which shifts displacement, effectively changing the
speed from a low range to a high range. Even with this arrangement,
Fan Speed is proportional to Engine Speed because of pump in the PS
runs according to the accessory drive belt ratio.

The Fan is controlled by the Engine Controller and responds to Coolant
Temperature and AC Head Pressure to turn on or change ranges.

My '01 4.7 WJ consistently ran coolant temperatures indicated at the
halfway mark on the gauge. No problems ever, tremendous amounts of
airflow from the fan. The biggest problem I had was groaning in the
high pressure oil lines after the isolators got old and hard.

Blockage of course (bugs, debris, cottonwood fuzz etc.) will reduce
airflow a lot, even with a powerful fan leading to overheating.

4.7's also have an inlet side T'Stat and '00's and '01's had some
problems with the coolant chamber mixing hot and cold and the correct
function of the T'Stat.

The 4.7 also has a coolant bleed screw on the top of the T'Stat
housing because it is higher than the radiator fill neck and will trap
air. Remember to bleed out the air after changing coolant or if
you've let the CRS bottle run low and it aspirates air into the
system.

reboot


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