Electric fan + 4.0 liter owner question: what temp?

imactj2004

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If you have a 4.0 AND you have an electric fan setup, I’d like to know what temperature your fan sender unit is turning ON and OFF?

And subquestion: are you still using a 195 thermostat or….?
 
I can tell you're not necessarily looking for this conversation/question, but why are you deviating from the tried and true with the 4.0L? Why move from the engine run setup?
 
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I can pretty much assure that most are going to say get rid of the electric and go back to OEM.

l.gif
 
If you have a 4.0 AND you have an electric fan setup, I’d like to know what temperature your fan sender unit is turning ON and OFF?

And subquestion: are you still using a 195 thermostat or….?

When my jeep arrived roughly two years ago, the PO was such a fucking dumbass that it's almost embarrassing to even mention.

He had a temp switch at 180 for the e-fan, which is dumb because the engine isn't even up to temp yet (thus forcing a full-duty cycle on the fan which likely caused the switch to fail and the fan to cut out). Edit: he also had a 210f thermostat installed lol.

If I had to run an E-fan, I would run a fan that turns on at let's say 210 to 215. That way it drops temps back down towards where the 195 thermostat opens, thus, the fan isn't on all the damn time. I'd likely do 210f for that reason. FWIW, my car's OEM fan used to turn on at 215 to push it back to 195f.

That's my logical guess, but I can't say from experience because I gutted it all and went to Mopar as my first work on the vehicle (because it overheated to 260f boiling my coolant during the smog test on my first ever drive...I was not happy to find out the PO was a lying fuck face when he adamantly claimed it "has no problem runs great!"

Just know that if your fan switch or fan goes out as mine did at 100 degrees ambient, you will be wishing you had a Mopar viscous fan clutch on there as you pray that your engine is not damaged.

Not trying to scare you but I'm also not wishing my experience on anyone.
 
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I have an Electric pusher fan I installed in addition to the stock mech one. T-stat is still 195, fan comes on at 210 and back off at 200. Works great for me cycles some in the summer but almost never comes on in the winter.

Mishimoto makes a decent controller kit if you just need a simple on/off. Wish I could figure out how to tie it to the PCM and get more control.
 
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Yes as above a 195 degree thermostat is correct. You definitely don't want the electric fan running 100% of the time so I'd be looking for it to turn on above 210, one post I read said 221 degrees which sounds reasonable to me.

I'm definitely no expert on electric engine fans for the 2.5 or 4.0 engine other than I'll never run one. If I bought a used Jeep that had one I'd remove it and convert it back to what the factory installed. :)
 
The stock viscous fan engages with a radiator leaving air temp of about 170, so I would want a switch that switched at an ECT that corresponded with that. Previous posters suggesting in the 210 range are probably right on the money.
 
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The stock viscous fan engages with a radiator leaving air temp of about 170, so I would want a switch that switched at an ECT that corresponded with that. Previous posters suggesting in the 210 range are probably right on the money.
I'd think a fan thermostat temperature little above 210 would be better since if it turned on at 210 that would cause the fan to run 100% of the time in most conditions.
 
Someone please educate me on this one, as I‘ve never understood the logic of having the fan come on a a higher temp than the engine thermostat. Although I have read of custom radiator companies making this very recommendation.

I don’t want the radiator dumping coolant into the engine that is hotter than the engine - that make no sense to me. I run a 180 degree thermostat (easy fellers, remember I’m not running a 4.0🙂) and a 170 fan controller - which works very well for me.

I run a variable speed fan which does usually run at low speed, but rarely at full speed. But it’s certainly not a daily driver, so I’m not worried about fan life.

So help a guy out: What am I missing here?
 
Someone please educate me on this one, as I‘ve never understood the logic of having the fan come on a a higher temp than the engine thermostat. Although I have read of custom radiator companies making this very recommendation.

I don’t want the radiator dumping coolant into the engine that is hotter than the engine - that make no sense to me. I run a 180 degree thermostat (easy fellers, remember I’m not running a 4.0🙂) and a 170 fan controller - which works very well for me. I run a variable speed fan which does usually run at low speed, but rarely at full speed. But it’s certainly not a daily driver, so I’m not worried about fan life.

So help a guy out: What am I missing here?

What? In what situation is your radiator coolant hotter than your engine?
 
Someone please educate me on this one, as I‘ve never understood the logic of having the fan come on a a higher temp than the engine thermostat. Although I have read of custom radiator companies making this very recommendation.

I don’t want the radiator dumping coolant into the engine that is hotter than the engine - that make no sense to me. I run a 180 degree thermostat (easy fellers, remember I’m not running a 4.0🙂) and a 170 fan controller - which works very well for me.

I run a variable speed fan which does usually run at low speed, but rarely at full speed. But it’s certainly not a daily driver, so I’m not worried about fan life.

So help a guy out: What am I missing here?

The coolant is heated by the engine so it shouldn't be any hotter than the engine.
 
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Someone please educate me on this one, as I‘ve never understood the logic of having the fan come on a a higher temp than the engine thermostat. Although I have read of custom radiator companies making this very recommendation.

I don’t want the radiator dumping coolant into the engine that is hotter than the engine - that make no sense to me. I run a 180 degree thermostat (easy fellers, remember I’m not running a 4.0🙂) and a 170 fan controller - which works very well for me.

I run a variable speed fan which does usually run at low speed, but rarely at full speed. But it’s certainly not a daily driver, so I’m not worried about fan life.

So help a guy out: What am I missing here?

I don't think the coolant going in would ever be hotter than what's coming out. On the contrary, I don't think dumping a radiator full of cold coolant into a hot engine is probably very good for it.

Since the thermostat sets the lower limit and the fan sets the upper limit, setting the fan below the thermostat just makes it so the fan is always on. I'd rather get at least some range where the fan isn't running. I don't think I'd go to 221 though, I'd probably stick with 210. Unless it was variable speed and I could set a proportional band to first turn on at minimum speed in the low 200s and max out at 215-220 or something.