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Converting electric fan cooling system back to original system?

netpoint

New Member
Joined
Nov 26, 2021
Messages
7
Location
Phoenix AZ
Hey guys,

Wanted to get your opinion and advice. I bought a 1997 TJ 4.0 few years ago and at some point in its life someone had installed an electric fan cooling system with a Dakota Digital PAC-3500 controller. Well not long after I had it it started overheating. I checked the PAC-3500 unit and it was throwing errors and not turning on the electric fans when hit temp (the fans would go on when starting the engine so the fans dont seem to be the issue.). So I thought the easiest thing to do was put a new temp sensor kit (one of those 185-200 Degree Electric Cooling Fan Thermostat Electric Fan 60 AMP Relay Kit) and bypass the PAC-3500.

I think I have all the wiring right but with the new sensor/unit its still not turning on the fans after initial start up and when Jeep hits temp.

I have read several times here that there is no point to "upgrade" to an electric fan system. What I want to know is should I just pull out the electric fan and install the old system? And if so I assume that would mean I would have to get a fan clutch and fan blades. Is there anything else would need, do or be concerned about?

Any thoughts/ideas/etc would be appreciated! Thanks and enjoy the holiday!

Aaron
 

kmbarreiros

TJ Enthusiast
Supporting Member
Joined
Dec 29, 2021
Messages
110
Location
Fairhaven, MA
Yep go back to the OE factory serpentine belt driven fan and never look back. It's better in all regards.

Is this statement the same for the 2.5l? I currently have the whole front of the engine apart and was considering doing an electric fan to get more out of my 4 squirrels. Is it also not worth it.
 

TJ4Jim

TJ Expert
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Joined
Dec 9, 2015
Messages
3,575
Location
Brookings, Oregon
Is this statement the same for the 2.5l? I currently have the whole front of the engine apart and was considering doing an electric fan to get more out of my 4 squirrels. Is it also not worth it.

Pretty much the same with the 2.5, running an electric setup really just transfers the load to the electrical system and as we all know there's no free energy.
 

cpwolf

Armed Texan
Supporting Member
Joined
Jun 15, 2020
Messages
1,054
Location
TEXAS - Cedar Park
Hey guys,

Wanted to get your opinion and advice. I bought a 1997 TJ 4.0 few years ago and at some point in its life someone had installed an electric fan cooling system with a Dakota Digital PAC-3500 controller. Well not long after I had it it started overheating. I checked the PAC-3500 unit and it was throwing errors and not turning on the electric fans when hit temp (the fans would go on when starting the engine so the fans dont seem to be the issue.). So I thought the easiest thing to do was put a new temp sensor kit (one of those 185-200 Degree Electric Cooling Fan Thermostat Electric Fan 60 AMP Relay Kit) and bypass the PAC-3500.

I think I have all the wiring right but with the new sensor/unit its still not turning on the fans after initial start up and when Jeep hits temp.

I have read several times here that there is no point to "upgrade" to an electric fan system. What I want to know is should I just pull out the electric fan and install the old system? And if so I assume that would mean I would have to get a fan clutch and fan blades. Is there anything else would need, do or be concerned about?

Any thoughts/ideas/etc would be appreciated! Thanks and enjoy the holiday!

Aaron


You need to look at a fan shroud as well, I think. The clutch and blades for the correct year.
 

Jerry Bransford

TJ Guru Moderator
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Nov 9, 2015
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25,435
Location
Fleming Island Florida
Is this statement the same for the 2.5l? I currently have the whole front of the engine apart and was considering doing an electric fan to get more out of my 4 squirrels. Is it also not worth it.
Yes equally true for the 2.5. Not to mention electric fans pull power from the engine too by making the alternator harder to turn from the higher electrical load pulled by the fan motor.
 
Joined
Jun 20, 2022
Messages
28
Location
NEPA
The "free energy" exists when you are moving and the electric fan shuts off. The mechanical fan cant disconnect from the engine. Your water pump will also live a longer life (maybe forever) with an electric fan. If you do a lot of highway driving the efan is the way to go. Throttle response is better, i have converted a few vehicles to electric and noticed this right away in warm weather. Other advantage for efans is the ability to force override for ac, hot days or force them off for water crossings so you dont suck mud and junk thru radiator fins.

If the system you bought to run the fan is t working it probably isnt hooked up right or temp not adjusted right. I have one with a small standalone relay that has a dial to adjust temp off a sensor thats shoved into the radiator. It needs to be located in the correct spot or it wont sense the temp increase, typically at the top where it goes back into the engine.
 
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netpoint

netpoint

New Member
Joined
Nov 26, 2021
Messages
7
Location
Phoenix AZ
Thanks everyone for your input! Really appreciate it. So if I convert back is it as simple as getting parts (1997 TJ 4.0):
- fan blade (something like DORMAN 621593 ?)
- fan clutch (not sure if need Hayden 2737 or Hayden 2625 (amazon says doesnt fit my jeep) or ???)
- fan shroud
- going to replace thermostat/gasket while at it so STANT 13789 although amazon says it doesnt fit my jeep??

Now assuming I just need those parts is installing them as simple as:
- bolt on fan blade to fan clutch
- install shroud
- bolt on blade/clutch assembly onto water pump
- drill 1/8 hole into thermostat and replace with gasket

Also thanks Approachmedium. I like what you said. I think everything is wired correctly and at this point i am at a loss in terms of what else could do without taking to a shop and have them try to figure it out (which trying to avoid for expense etc) Also you mentioned location of sensor, previous owner had put sensor towards the back/lower/drivers side of engine block which makes me wonder how much problem that has been causing with sensing temp increase.

Thanks again everyone for your input. I am a bit lost on what to do so really appreciate it.
 
Joined
Jun 20, 2022
Messages
28
Location
NEPA
Why are you drilling a hole in the t stat????

it does not belong on the engine block it belongs on the radiator, unless its the kind you drill and tap, those belong where the tstat housing is and THEN you would make a hole. Rear and bottom of engine is the coolest place to be. They are pretty simple to test and hook up. You need battery direct power, ground, and a key ignition source. Theres 3 basic wires for that which go to a relay. the relay should then have its coil power come from the temp sensor, and then the ignition switch. easiest way to test is jump this coil to 12v or ground depdning on your relay wiring and see if the fan runs. if it doesnt run, you def have a problem. If it is not connected to some kind of switched power, it also will never turn on.
 
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netpoint

netpoint

New Member
Joined
Nov 26, 2021
Messages
7
Location
Phoenix AZ
Why are you drilling a hole in the t stat????

it does not belong on the engine block it belongs on the radiator, unless its the kind you drill and tap, those belong where the tstat housing is and THEN you would make a hole. Rear and bottom of engine is the coolest place to be. They are pretty simple to test and hook up. You need battery direct power, ground, and a key ignition source. Theres 3 basic wires for that which go to a relay. the relay should then have its coil power come from the temp sensor, and then the ignition switch. easiest way to test is jump this coil to 12v or ground depdning on your relay wiring and see if the fan runs. if it doesnt run, you def have a problem. If it is not connected to some kind of switched power, it also will never turn on.

Regarding the hole, I had read about doing that a few times on this forum. It seemed several recommended it. I will try the jump test, thats a good idea. Thanks!
 

cpwolf

Armed Texan
Supporting Member
Joined
Jun 15, 2020
Messages
1,054
Location
TEXAS - Cedar Park
Thanks everyone for your input! Really appreciate it. So if I convert back is it as simple as getting parts (1997 TJ 4.0):
- fan blade (something like DORMAN 621593 ?)
- fan clutch (not sure if need Hayden 2737 or Hayden 2625 (amazon says doesnt fit my jeep) or ???)
- fan shroud
- going to replace thermostat/gasket while at it so STANT 13789 although amazon says it doesnt fit my jeep??

Now assuming I just need those parts is installing them as simple as:
- bolt on fan blade to fan clutch
- install shroud
- bolt on blade/clutch assembly onto water pump
- drill 1/8 hole into thermostat and replace with gasket

Also thanks Approachmedium. I like what you said. I think everything is wired correctly and at this point i am at a loss in terms of what else could do without taking to a shop and have them try to figure it out (which trying to avoid for expense etc) Also you mentioned location of sensor, previous owner had put sensor towards the back/lower/drivers side of engine block which makes me wonder how much problem that has been causing with sensing temp increase.
Regarding the hole, I had read about doing that a few times on this forum. It seemed several recommended it. I will try the jump test, thats a good idea. Thanks!

I agree with your earlier post, switch it, the stock cooling system is better. I hate the electric fan on out 08 Jk, that’s has been replaced now 3 times because it “got wet”, total BS.

Drilling a hole and positioning at 12 o’clock on the thermal stat won’t hurt it, and it may help burp it easier. Why not.

I’d make sure the shroud and fan Valdes all fit before you put them on, I can’t recall if the shroud will go on with the blade attached, might need to do it all in one kind of deal. I’m sure there’s a YouTube on it.
 

cpwolf

Armed Texan
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Jun 15, 2020
Messages
1,054
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TEXAS - Cedar Park
I should clarify, the electric fan setup sucks, to me. Free country, and I don’t need to hear the greatness of it, the TJ came with a setup that 100% works 100% of the time in 100% of weather in the USA, so I don’t see a need to change it.
 
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