Engine Fans

[UWMad]

So this happened to me recently and upon engine bay inspection ot looks like I had a cracked coolant line at the overflow reservoir. I had just climbed inside of the bay to replace plugs so I think i may have caused it but still something to check for.

 

[K223]

100% normal; mine does the same thing.

Im curious how are they regulated, meaning what information does the PCM/BCM etc use to regulate there speed besides some of the obvious like engine temp, A/C, etc. The truck sitting in my driveway this morning baking in the sun showed 114 on screen as the outside temp. Fired the truck up cold and AC on and instantly full fans. I’m thinking the exterior temp sensor also plays a roll.

 

[Deleted member 17706]

Im curious how are they regulated, meaning what information does the PCM/BCM etc use to regulate there speed besides some of the obvious like engine temp, A/C, etc. The truck sitting in my driveway this morning baking in the sun showed 114 on screen as the outside temp. Fired the truck up cold and AC on and instantly full fans. I’m thinking the exterior temp sensor also plays a roll.

Yes, the outside temps dictate when the fans kick on. If you have the AC fully on and it is 70 degrees out, then the fans won’t fully turn on. The fan noise on the Gen 2 is nothing compared to the Gen 1. Lol you couldn’t go through a drive-thru without turning off the Gen 1 because the fans are so loud.

 

[Ali 556]

The issue with ford fans is that there is no ramp up-ramp down curve in the settings at the pcm.

If it sees x degrees it will kick the high speed, on GM vehicles they have a pretty nice curve for ramping up the fan speed, that why on 05+ truck they are almost silent.

Add to that, the EB f150 in general has alot of crap behind the radiator, airflow is not optimal at all, get your hand in the fog lights pockets while the fans are on, and feel the wind from the fans, that's why ford keeping the stupid shutters to get some aerodynamic help in this truck.

 

[jabroni619]

Im curious how are they regulated, meaning what information does the PCM/BCM etc use to regulate there speed besides some of the obvious like engine temp, A/C, etc. The truck sitting in my driveway this morning baking in the sun showed 114 on screen as the outside temp. Fired the truck up cold and AC on and instantly full fans. I’m thinking the exterior temp sensor also plays a roll.

IF your AC is on, it’s hot out and you’re not moving I would be more worried if the fans don’t turn on. It doesn’t take the condenser long to get heat soaked in conditions like that if there’s no air flow.

 

[FordTechOne]

Im curious how are they regulated, meaning what information does the PCM/BCM etc use to regulate there speed besides some of the obvious like engine temp, A/C, etc. The truck sitting in my driveway this morning baking in the sun showed 114 on screen as the outside temp. Fired the truck up cold and AC on and instantly full fans. I’m thinking the exterior temp sensor also plays a roll.

The strategy is in the PCM since it directly controls the fans; it uses inputs such as Ambient Air Temp (AAT), Engine Coolant Temperature (ECT), Cylinder Head Temperature (CHT), and A/C system pressures (High/Low sides) to determine the fan speed.

 

[K223]

The strategy is in the PCM since it directly controls the fans; it uses inputs such as Ambient Air Temp (AAT), Engine Coolant Temperature (ECT), Cylinder Head Temperature (CHT), and A/C system pressures (High/Low sides) to determine the fan speed.

Makes sense now. Since it’s been an ambient temp of 95 or close to it and take into account the sun heating up the shell of the truck. It’s showing an ambient of 108-114 during the day. That’s surely what’s turning the fans up to full upon startup. At night the fans were at a normal slow speed.

While I can see the truck taking one input and going to maximum cooling, on a cold start. The coolant temp and AC system can’t possibly be that high to warrant it. But I won’t pretend to have engineered them truck and the reasoning behind it. 114 registering at the AAT is of concern in the grand scheme of things in remaining cool.

While on the fan subject, what’s the strategy that controls the IC fans?