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I am installing a new radiator with electric fans following a wreck. I am planning to set the PWM To come on at 60% at 195 degrees F and hit 100% at 205F. This is the return temp to the engine I'm referring to. Am I off on my number? Should I shoot for a different number? I'm not sure what temp the mechanical clutch activated at.

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when will the fans come back down/off? 10* below when they turn on? 15*? do you want the low speed to turn off and on as you drive? is there separate control to turn on for A/C?

i like to have my fans come on alittle sooner than operating temp so it helps stop fluctuations. it will also pretty much always stay on low speed once it gets up to temps cause i dont like hearing the fans come on and off constantly. my friends fans are dual 1-speed and are LOUD and he has them so they turn off and on constantly and it annoys me

my trucks are not PWM. my 88 is single 2-speed fan. my 96 is a dual 1-speed fan. my F250 is a dual 2-speed fan. all 3 run on a dual temp switch that is 188-170 low / 198-180 high.
the F250 despite being dual 2-speed, i have it so 1 fan is on all the time low, the other fan comes on when switch kicks on low, then the first fan kicks on high when the switch kicks on high.
 

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95 f-150 4x4 5.8 e4od 05 F250 axles w/4:10's lifted/modded owned since 97 w/28K
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depends on where your picking up the temp? my cobra controller i ran years ago went into the radiator and which is cooler than the engine. i had to set it around 180 whilst in the radiator to keep my gauge in the middle of the normal.

they don't need to run all the time, as long as its got a soft start function, and doesn't come on wide open, and depending on the fans location/brand/etc. they should be as quiet as modern vehicles. i use both in my rig. a H/D fan clutch and efan hooked up to my a/c cycle switch. so the clutch fan runs all the time, and efan cycles with the compessor for the a/c.
 

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location of the sensor is a good point. i put my sensors inline of the heater hose. it and bypasses the t-stat so its always flowing. an issue with this is low coolant can cause it to read bad.

if you put it in the upper radiator hose or t-stat housing, when the t-stat closses it will be slow to read since there wont be any flow or any way to cool it.

putting it on the radiator itself i feel is problematic but alot of vehicles put the radiator fan switches on the tank of the radiator.
 

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95 f-150 4x4 5.8 e4od 05 F250 axles w/4:10's lifted/modded owned since 97 w/28K
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the fan controller i purchased was only fitted to a radiator cooling fins unfortunately but i agree, not the best place to monitor engine temp. the best area to pick up the temp imho is the "tree" in the intake manifold just before the thermostat where the oem one is. i believe thats the one the computer reads and the driver side coolant sensor is for the gauge in the cluster.
 

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'88 XLT. 2" lift, 3G, Saginaw Pump, Headers, High flow 3" cat, 3" exhaust, 6 litre tune, K&N
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I opted for full manual control with a lighted dash switch that triggers a heavy duty relay powered by the battery. I don't trust any of the import aftermarket fan controls. I overheated once already from a cheap overseas import relay that came in a fan relay kit. I don't trust a kit to have my fan come on when it needs it. I would rather have full manual control on when the fan runs.

The only problem is you have to be careful who you lend your bronco to. Has to be somebody who actually can and will look at the temperature gauge. Which, now a days is nobody under 25 years old.........🤣.

Where I live, about 75% of the time I don't even need to turn on the fan except in summer or stop and go traffic. My fan is from a '00 Police Interceptor and it is wired to high, which is around 4,000 cfm, probably draws almost 30 amps on start up.
 

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I opted for full manual control with a lighted dash switch that triggers a heavy duty relay powered by the battery. I don't trust any of the import aftermarket fan controls. I overheated once already from a cheap overseas import relay that came in a fan relay kit. I don't trust a kit to have my fan come on when it needs it. I would rather have full manual control on when the fan runs.

The only problem is you have to be careful who you lend your bronco to. Has to be somebody who actually can and will look at the temperature gauge. Which, now a days is nobody under 25 years old.........🤣.

Where I live, about 75% of the time I don't even need to turn on the fan except in summer or stop and go traffic. My fan is from a '00 Police Interceptor and it is wired to high, which is around 4,000 cfm, probably draws almost 30 amps on start up.
thats why i wire my own relays up and use a dual temp switch instead of controllers. its automatic but no electronics. ive had a few of the cheap Imperial fan controllers melt or break. and my friends Derale electronic fan controller has been problematic sometimes. the DCControl controller takes a long time to get and i question its use for offroad. also i can still wire an dash switch so i can have an Auto-Off-High switch in the cab if desired.

the e-fans i have in my F250 and 96 Bronco are from a 2017 Lincoln MKC. they are very thin and fit the radiator almost perfectly but are alittle tricky to get mounting setup due to being soo thin. they are dual fans with resistors for the option of 1 or 2 speed each depending on the wiring harness. each fan on low draws 13 amps and each fan on high draws 20 amps each, so they push a good amount of air. but it also means good amount of wiring

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the most common dual temp switch is the BMW temp switch. but ordering the connectors are kinda annoying and expensive. also the switch is very tall. ive used it on a few trucks. but latley i have been using a Volkswagen dual temp switch and i like better. and issue is that its a weird M22 thread nobody makes coolant adapters for. so i make my own T fittings. like i said i place them inline of the heater hose. the T fitting is a 3/4" PEX 'drop ear tee' that i drill n tap for M22 thread

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my 88 is using a Crown Vic 2-speed signle fan e-fan. but it is very large and only works on trucks with body lifts as it turns out. but it does cool good and easy to mount, fits radiator very well. im using the same dual temp switch but using a Volvo 2-speed fan relay for it. think it daws like 18amps low and 28 amps high if i remember. it keeps the mud truck running very cool, untill it burns out. i have it wired to dash switch for Auto-Off-High, but i keep forgetting to turn it off when crossing water. i need to rig a float switch to shut it off whenever water gets high

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95 f-150 4x4 5.8 e4od 05 F250 axles w/4:10's lifted/modded owned since 97 w/28K
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i run both, heavy duty fan clutch and electric fan

efan comes on when the a/c compressor kicks on.

if it goes out, im still good.

my fan controller is a cobra which is made in the usa, not a cheap china, all my relays are heavy duty 80amp continuous duty relays, all wiring gets auto style crimps, dielectric grease and usually dual ground points.
 

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'88 XLT. 2" lift, 3G, Saginaw Pump, Headers, High flow 3" cat, 3" exhaust, 6 litre tune, K&N
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Kingfish999,

I gave up trying to figure out the two speed works on the Crown Vic fan. I didn't know about the Volvo relay at the time. I might get me one of these next time I am at the junkyard.
Do you have a diagram of how to wire the Volvo 2 speed fan relay?

My crown vic fan and shroud did fit, but took some trimming. I don't have a body lift. I believe I cut a triangle out of each side and trimmed the top, so the fan didn't tilt. The fan shroud is wedge shaped on the Crown Vics. I did have to remove the mechanical fan assembly.
 

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the volvo system works good, ive installed a few and will have to find my notes but there should be PLENTY diagrams on google or loosertube

the volvo system i put in, iirc, kicked on at around 50% like a soft start, after a certain time if temps did not decrease, then it would cick on to high
 

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Kingfish999,

I gave up trying to figure out the two speed works on the Crown Vic fan. I didn't know about the Volvo relay at the time. I might get me one of these next time I am at the junkyard.
Do you have a diagram of how to wire the Volvo 2 speed fan relay?

My crown vic fan and shroud did fit, but took some trimming. I don't have a body lift. I believe I cut a triangle out of each side and trimmed the top, so the fan didn't tilt. The fan shroud is wedge shaped on the Crown Vics. I did have to remove the mechanical fan assembly.
i tried to put the Crown Vic fan on my 96 without a body lift and it hit the water pump pulley. othereise i used it on my 88 and 2 of my friends trucks, all with body lifts.

what year Crown Vic do you have it from? does it use a resistor? the ones i used did not have a resistor, they are a true 2 speed fan and apparnetly have to be wired differently. there was another identical version used on the later years that did use a 1-speed motor with a resistor for low speed and wiring it is simpler.

theres alot of threads over google on how to use the Volvo relay. its pretty simple but does require another relay (otherwise the fan will run with engine off)..

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if you wanted to add a dash switch for Auto/Off/On then you would move the normal relay to control the ground for the switch. id have to make a diagram when i got time
 

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the volvo system works good, ive installed a few and will have to find my notes but there should be PLENTY diagrams on google or loosertube

the volvo system i put in, iirc, kicked on at around 50% like a soft start, after a certain time if temps did not decrease, then it would cick on to high
I was interested in an Efan but I don’t know a lot about it. Did you notice any performance gains? Specifically MPG?


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'88 XLT. 2" lift, 3G, Saginaw Pump, Headers, High flow 3" cat, 3" exhaust, 6 litre tune, K&N
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This is officially a threadjack within a thread jack now. :LOL:

To the OP:

I do not see any problem with the temp ranges you have posted but you did not post your thermostat reading. I would think the bottom (low speed) temp setting would be around your thermostat setting. With the sensor set on the return line, there is the possibility of overheating if your thermostat never opens, the fan won't kick on since there is no coolant flow. So I would drill a hole in it. I do not know how accurate these temperature sensors are. If they are +/- just a few degrees, your settings may be fine. If they are +/- 5 degrees or more, than you might need to set the upper limit a little higher, or the lower limit lower so you have more overlap and fan cycling between high and low during normal driving if you are at 200 F.
 

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This is officially a threadjack within a thread jack now. :LOL:

To the OP:

I do not see any problem with the temp ranges you have posted but you did not post your thermostat reading. I would think the bottom (low speed) temp setting would be around your thermostat setting. With the sensor set on the return line, there is the possibility of overheating if your thermostat never opens, the fan won't kick on since there is no coolant flow. So I would drill a hole in it. I do not know how accurate these temperature sensors are. If they are +/- just a few degrees, your settings may be fine. If they are +/- 5 degrees or more, than you might need to set the upper limit a little higher, or the lower limit lower so you have more overlap and fan cycling between high and low during normal driving if you are at 200 F.
well OP hasnt responded so its hard to give too much more info without knowing more about his setup

what exactly do you mean by 'return line'? the small bypass hose between t-stat and water pump? heater return? radiator return? none of which i would recommend
the small bypass hose between WP and t-stat is too small to connect to. the heater return will have greatly affected readings if he ever uses heat. radiator return is far from 190*
really the only place to add it would be intake coolant port or heater supply hose. which is why the factory EFI uses that area. it bypasses the t-stat so its never stagnant water.

most t-stats already have a hole with a little metal piece in it already. just take the metal piece out.
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I was interested in an Efan but I don’t know a lot about it. Did you notice any performance gains? Specifically MPG?
it frees up some HP and lets the engine accelerate alittle quicker. but you wont see much gain in MPG unless you idle a ton. once the truck moving at good speed, the fans do not do much so any gains will be at idle or low speeds. its always a big debate which to use

a debate about efan vs mechanical is that "mechanical fan will always move more air". the problem is that the shrouds for mechanical fans are not very tight to the fan so they loose alot of efficiency. if the shrouds are broken or missing then they really suffer. efans have the shroud very tight to the fans so they are more efficient. but the efans do need to be pretty tight up to the radiator or they suffer.

aftermarekt fan clutches tend to be pretty low quality and fail often. also they can make the waterpump go bad sooner if the fan is imbalanced. efans do occasionally burn out but are pretty reliable if wired correctly. you can run them with the engine still off which is nice. they let the engine get to temp quicker because they wont turn on till its hot. a good efan can be much quieter than mechanical but there are some LOUD efans out there
 

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The OP said the return temp to engine, so the water temperature as it leaves the radiator.

I didn't see any real MPG change using an electric fan, but I did gain a few mph on a hill I always drive on. Before I always had to shift to 3rd to maintain 50 - 55 mph, now I can keep it there in overdrive, barely, with the fan turned off, so a few hp worth of parasitic hp saved. If the electric fan was on, that is out the window since the alternator has hp loss. That could be a few tenths of a mpg.

The best part of the manual electric fan switch, is with the fan off I don't have to smell as much leaking burning oil on the exhaust at stop lights :ROFLMAO:
 

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95 f-150 4x4 5.8 e4od 05 F250 axles w/4:10's lifted/modded owned since 97 w/28K
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the only thing i noticed when i ran just the efans was a drop in voltage when they kicked on, and faster temp drops, with a 130amp alternator at the time.

i noticed zero performance or torque or mpg increase, so i went back to the stock clutch, but since i have a body lift, that causes the a/c to not get as cold in texas summer traffic so i installed an electric helper fan to aid the stock fan clutch. works really well.

the efans worked, they cleared up some room under the hood. did i notice a power increase? no
 
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Engine Masters did an episode on how much different fans draw. this is on a dyno with a 350hp engine but they did setup a radiator with shroud to simulate it. it lost like 14hp with a standard clutch style fan. on a engine making 200hp thats going to be more significant. and people using the HD clutches will also lose more. they also tested other fan configurations.

on my trucks, especially mt F250, i noticed a decent gain. but i also keep my engine at higher rpm than most truck people. i am not scared of holding it at 5k rpm. as you can see the power loss is more at higher rpm


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ive got a set of underdrive pullys that dramatically reduced all the accessory strain on the engine, i could tell a big difference with the pully swap, so in my case, its probably a wash. the only time a heavy duty fan clutch really robs a ton of power is when its not free spinning when it reaches higher temps.

again, i didn't feel a single performance gain except for a little better throttle response, and thats a maybe. but theres a lot of dyno proof, especially on mustangs that proovs that it robs power.
 
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