Hey guys,

I'm still getting used to my new truck so not sure if this is normal or not...

Driving around town doing errands yesterday, I went into a store and when I came out and started up the truck, the engine fans ramped up to full speed for about 15 seconds, then either slowed to normal or turned off. I've never had this happen yet so it got my attention.

The outside temps were around 22C or 72F. The HVAC was just set for LO and fan on speed setting 2 through the mid and floor vents. No AC was selected.

 

Howdy!

Entirely normal - mine does that under certain conditions as well.

Cheers
MGD

 

2013 - 2016 F150, And 2015 - 2016 Expedition/Navigator Low Speed A/C Performance Enhancement - Cooling Fan Strategy Update

2013 - 2016 F150, and 2015 - 2016 Expedition/Navigator Engine Cooling Fan strategy has been changed to improve low vehicle speed A/C performance. The Engine Cooling Fan is more noticeable at higher ambient temperatures than previous model years. This is a normal condition to improve low vehicle speed A/C performance, and no repair should be attempted

 

Thanks for the replies. I didn't have AC on at the time.

 

Hmmm... Did it again yesterday morning. Stopped in to get a coffee at Starbucks and came out, started the truck, and the cooling fans ran at full speed for about 10 seconds. Again, the AC was not on. Outside temp was about 18C or 64F.

I wonder why this happens? They are quite loud when they run at full speed.

I looked through the factory service manual but it doesn't seem to say much about the operation of the cooling fans. At least not that I could find.

 

Mine does the same thing - both with AC on and off. I believe it's normal. With the AC off, it may be largely dependent on engine temp. So if you're engine temp was elevated when you started truck again after coffee, even if outside temp was a cool 64 degrees, the fans might have kicked in to cool engine before you began moving, thus allowing airflow into engine.

 

When you shut off your engine and the water stops circulating the water in the block absorbs more heat so the engine becomes heat soaked. When you crank it after a short time the temperature is above normal operating temp thats why the fans ramp up. The reason they slow down so quick is because the cooler water from the radiator quickly circulates into the block and the temp sensor quickly falls into normal temp range.

 

I get that too sometimes. If you shut the truck off before the coolant goes down to 93*C and restart the truck, the rad fan will come on full blast to bring the coolant down. That's why I will let my truck idle down to 93*C before shutting down (totally overkill for a gasser, as I do the same for my diesel but also monitor EGT).

 

Interesting. Thanks for the info. That all makes sense.

 

Mine has been doing it regularly lately... Of course it in the 100s