electric fan turn on temp
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Joined: Oct 2009
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From: Central Connecticut
I have a brand new 195 temp thermostat in it. I think I have a bad controller, my Livewire is reading 196(don't know how accurate that is) as the highest temp after running on the at 90 for 30 miles and its set at the lowest which is 160 but the fan only ran for a little bit off and on. it was 23 outside when i was on the highway.
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Joined: Oct 2002
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From: St. Louis (Out in the woods)
Where is the temperature sensor for the add-on controller mounted?
At 23F outside temp and 90 MPH speed, the sensor might be getting cooled down to the point that it thinks the coolant temp is fine.
At 23F outside temp and 90 MPH speed, the sensor might be getting cooled down to the point that it thinks the coolant temp is fine.
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Joined: Nov 2008
Posts: 4,324
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From: swamps of la
thats fine, my truck would run 188-190 on the highway in the summer and 182 in 30 degree weather. i didnt even run a fan at all last winter! 
in the summer it would spike to almost 210 before the fans would kick on. no big deal.
in the summer it would spike to almost 210 before the fans would kick on. no big deal.
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Joined: Jul 2004
Posts: 6,200
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From: Easton, Pa.
To add some comments, this can become a complex issue because of differences in ambient temps, speed of travel, where the sensor is placed etc.
As for thermostat temp, 195 to 200 is the spec for these motors and what the PCM expects to base it's table adjustments on in the program.
Running cooler will tend to increase fuel consumption as well as have an effect on cooling.
I will admitt that a very sleight increase in torque might be felt under maney conditions from the cooler running and richer fuel rates at high throttle opening.
My experience with a new thermostat is as new it right on 198 to 202 but see it is backing down in it's lower temp as time goes on.
Good luck.
As for thermostat temp, 195 to 200 is the spec for these motors and what the PCM expects to base it's table adjustments on in the program.
Running cooler will tend to increase fuel consumption as well as have an effect on cooling.
I will admitt that a very sleight increase in torque might be felt under maney conditions from the cooler running and richer fuel rates at high throttle opening.
My experience with a new thermostat is as new it right on 198 to 202 but see it is backing down in it's lower temp as time goes on.
Good luck.
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Senior Member
Joined: Nov 2008
Posts: 4,324
Likes: 6
From: swamps of la
As for thermostat temp, 195 to 200 is the spec for these motors and what the PCM expects to base it's table adjustments on in the program.
Running cooler will tend to increase fuel consumption as well as have an effect on cooling.
I will admitt that a very sleight increase in torque might be felt under maney conditions from the cooler running and richer fuel rates at high throttle opening.
My experience with a new thermostat is as new it right on 198 to 202 but see it is backing down in it's lower temp as time goes on.
Good luck.
Running cooler will tend to increase fuel consumption as well as have an effect on cooling.
I will admitt that a very sleight increase in torque might be felt under maney conditions from the cooler running and richer fuel rates at high throttle opening.
My experience with a new thermostat is as new it right on 198 to 202 but see it is backing down in it's lower temp as time goes on.
Good luck.
not sure if this was directed towards me, but, i agree, and my motor is a little different than a base f150 and im programmed to run that T-stat.
That said, I have my fans selected to come on at 210*F and off at 205*F. Keep in mind the fans are not a primary coolant, the water is. The fans are backup to help cool excess heat when you are not moving. I know people running fans at 190-195 degrees wondering why they have to keep replacing fans every year
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Joined: Jul 2004
Posts: 6,200
Likes: 39
From: Easton, Pa.
RAPTOR you have some things wrong.
185 degrees is not low enought to cause open loop operation.
The programmed threshold is 175 out of Ford documentation, then it sets a code 125 at that point or lower.
Next, adding fuel does not cause extra heat in the motor, it causes cooling.
If you don't agree with this, research it.
On a race motor you would never lean out to cool the motor down or add fuel to heat it.
To explain it, combustion air to fuel ratio is based on just enough over fueling to keep the piston and combustion chamber from going to hot melting piston crowns, burning plug tips and causing overheating.
If this would happen, the CHT detects it and cause the PCM to go into limp mode where every other cylinder on a rotating basis has it's fuel shut off to allow thoses cylinders to pump air only, eliminating combustion.
.
After normal combustion, there should be some small amount unburned fuel left in the exhaust to be proper in all gas engines.
The OX sensors are calibrated for this.
Take away the small excess of fuel OR add more air and the motor begins to run lean and heats up, the OX sensors detect it and feeds a signal back to the PCM to richen the fuel tables.
This is the basis for the codes 171/174 and 172/175.
The only times the motor is 'normally' in open loop is at cold starting and wide open throttle at about 7/8 or greater..
This time interval for cold starting is only until the OX sensors heat up to about 600 degrees to enable them to output a usefull control signal to the PCM.
They have electric heaters to shorten the time.
Any other time is due to a fault rendering the OX sensors unable to track the A/F ratio or some other fault.
If a fault such as this does occurr the fuel tables are reverted to 'that are richer' to cool the motor and protect it not heat it more.
Good luck. Hope you not insulted by the lecture..
185 degrees is not low enought to cause open loop operation.
The programmed threshold is 175 out of Ford documentation, then it sets a code 125 at that point or lower.
Next, adding fuel does not cause extra heat in the motor, it causes cooling.
If you don't agree with this, research it.
On a race motor you would never lean out to cool the motor down or add fuel to heat it.
To explain it, combustion air to fuel ratio is based on just enough over fueling to keep the piston and combustion chamber from going to hot melting piston crowns, burning plug tips and causing overheating.
If this would happen, the CHT detects it and cause the PCM to go into limp mode where every other cylinder on a rotating basis has it's fuel shut off to allow thoses cylinders to pump air only, eliminating combustion.
.
After normal combustion, there should be some small amount unburned fuel left in the exhaust to be proper in all gas engines.
The OX sensors are calibrated for this.
Take away the small excess of fuel OR add more air and the motor begins to run lean and heats up, the OX sensors detect it and feeds a signal back to the PCM to richen the fuel tables.
This is the basis for the codes 171/174 and 172/175.
The only times the motor is 'normally' in open loop is at cold starting and wide open throttle at about 7/8 or greater..
This time interval for cold starting is only until the OX sensors heat up to about 600 degrees to enable them to output a usefull control signal to the PCM.
They have electric heaters to shorten the time.
Any other time is due to a fault rendering the OX sensors unable to track the A/F ratio or some other fault.
If a fault such as this does occurr the fuel tables are reverted to 'that are richer' to cool the motor and protect it not heat it more.
Good luck. Hope you not insulted by the lecture..
Last edited by Bluegrass; Dec 7, 2012 at 08:19 PM.
