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 --- avast! Antivirus: Outbound message clean. Virus Database (VPS): 000782-2, 10/18/2007 Tested on: 10/19/2007 12:28:54 AM avast! - copyright (c) 1988-2007 ALWIL Software. http://www.avast.com |
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 --- avast! Antivirus: Outbound message clean. Virus Database (VPS): 000782-2, 10/18/2007 Tested on: 10/19/2007 12:28:54 AM avast! - copyright (c) 1988-2007 ALWIL Software. http://www.avast.com |
Re: fluid drive cooling fan
On Fri, 19 Oct 2007 01:51:34 GMT, "Jeff Strickland"
<crwlr@verizon.net> wrote: > >"juiceman" <juiceman5150@gmail.com> wrote in message >news:1192756499.336687.296200@k35g2000prh.googleg roups.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. > > pulse width modulated 'Tis a way of controling speed using essentially a square wave signal with varying on-times. -- Old Crow "Yol Bolson!" '82 FLTC-P "Miss Pearl" '95 YJ Rio Grande BS#133, SENS, TOMKAT, MAMBM -- Posted via a free Usenet account from http://www.teranews.com |
Re: fluid drive cooling fan
On Fri, 19 Oct 2007 01:51:34 GMT, "Jeff Strickland"
<crwlr@verizon.net> wrote: > >"juiceman" <juiceman5150@gmail.com> wrote in message >news:1192756499.336687.296200@k35g2000prh.googleg roups.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. > > pulse width modulated 'Tis a way of controling speed using essentially a square wave signal with varying on-times. -- Old Crow "Yol Bolson!" '82 FLTC-P "Miss Pearl" '95 YJ Rio Grande BS#133, SENS, TOMKAT, MAMBM -- Posted via a free Usenet account from http://www.teranews.com |
Re: fluid drive cooling fan
On Fri, 19 Oct 2007 01:51:34 GMT, "Jeff Strickland"
<crwlr@verizon.net> wrote: > >"juiceman" <juiceman5150@gmail.com> wrote in message >news:1192756499.336687.296200@k35g2000prh.googleg roups.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. > > pulse width modulated 'Tis a way of controling speed using essentially a square wave signal with varying on-times. -- Old Crow "Yol Bolson!" '82 FLTC-P "Miss Pearl" '95 YJ Rio Grande BS#133, SENS, TOMKAT, MAMBM -- Posted via a free Usenet account from http://www.teranews.com |
Re: fluid drive cooling fan
how about checking cooling system level first then fault codes but thats too
simple ay! juiceman wrote: > 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
how about checking cooling system level first then fault codes but thats too
simple ay! juiceman wrote: > 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
how about checking cooling system level first then fault codes but thats too
simple ay! juiceman wrote: > 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. |
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