A search, like always, popped up with dozens of posts. Spent the last half hour reading more than I can count and nothing. The way a search here always ends up.
.
So, I understand shutters on a diesel engine, but what are they doing on our gas trucks?
We don't control temperatures with thermostats any more?

 

Its for efficiency. Closed to get temp up to temp faster, closed at highway speed for better aerodynamics, etc. Of course for us the difference is fractional and nothing dramatic. I'm sure its nothing more than to help meet regulations.

 

When they're open, the Active grille shutters allow air to flow through the radiator and into the engine compartment, as usual, to promote cooling. But when that cooling air is not needed, the shutters close, rerouting air around the vehicle to lessen aerodynamic drag and reduce fuel consumption. As an added bonus, closed shutters also reduce warm-up time in cold weather.

 

You have it backwards. Primary purpose is for a quicker engine warmup. Aerodynamics is the secondary benefit. Turn on the A/C, and the shutters default to open regardless of speed.

 

Thanks for the info.

 

Shutters may indeed open anytime A/C is on (don't know, haven't studied it), but Ford touted the shutters in the F150 as being part of the aerodynamic design, to improve mileage.

Replacing a overboost sensor in my wife's 2013 Escape this weekend, found it also has shutters, and they cover a lot larger area of the radiator than the F150, and the airflow is segmented so the shutters truly block the top half of the radiator, rather than just blocking part of the grill like in the 150.

 

On my 2016 5.0 2wd, the shutters stay open when the A/C is on. The temperature will stay between 200 and 206. That's with the ambient temperature over 100 degrees, and cruising west Texas at 80 mph, or Arizona at 75 mph at 115 degrees ambient temperature. If I turn off the A/C, the temperature will climb as high as 229 degrees, then drop back to 205. It will fluctuate as long as the a/c is off. It does not do this if I unplug the shutters. The temp will seldom climb above 210 degrees.

I had the shutters unplugged for awhile, but I realized the difference in engine warm up time made a difference in fuel mileage driving around town. And considering that I seldom travel in 100 degree weather without the a/c on, I gained nothing by keeping the shutters unplugged.

 

Not disputing that, just stating that Ford focused on fuel economy. It's obvious they can impact cooling as they block airflow when closed, and Ford without a doubt programmed the system to open them anytime max heat removal is required, but per their marketing, they are there for economy/emissions.

They aren't needed to assist in warm-up, as both the engine and transmission have thermostats that keep the fluids from moving through the radiators until minimum temp is met.

If your truck is definitely warming up faster with the shutters closed, you may have a thermostat that is not closing fully. Thermostats are cheap devices, and are designed to fail to fully close if the pill becomes contaminated, although they occasionally will get stuck closed. I've never experienced a stuck closed thermostat, on all of our Fords, they have either failed to completely close, or had total wax loss and stayed fully open.