Whenever I start my truck in warm weather, the fans initially run normally for a few seconds before ramping up to high speed. There are no trouble codes or system abnormalities, but the noise is quite annoying. Does anyone have any ideas on why this might be happening?
Just to clarify, the engine isn’t overheating; the temperatures are normal, the coolant level is fine, and this issue starts at 75 degrees Fahrenheit or higher, which isn’t very hot.
Is the A/C on I mean running?
Yes but it also does it when the AC is off
The fans are activated by a temperature switch. It is normal for engine fans to run when the truck is idling, particularly if the A/C is on. They typically turn off once you start driving, as the airflow from driving makes the fans unnecessary.
There are TSBs for this issue: 21-2250 and 22-2089.
I have been dealing with Ford and warranty on this and they want thousands of dollars to replace parts before they’ll acknowledge and fix the problem, assuming your warranty has expired.
If your A/C is blowing cold air and everything else is working fine, the problem is usually one of two things:
The evaporator temperature sensor is faulty and needs replacement, which Ford says requires removing the dashboard and is very expensive.
Alternatively, you can use an A/C recharge kit with a gauge from NAPA. Run your A/C on full blast, connect the gauge to the low-pressure A/C line under the hood, and don’t add any refrigerant—just use the gauge. If the gauge is off the chart, slowly loosen the fitting until you hear a hiss. If air comes out but no refrigerant, let the air out and check the gauge until it’s in the green zone. This should stop the fans.
If you see any refrigerant (which is yellow), stop immediately.
Background: Ford hasn’t been able to resolve this. I’ve taken my F150 to the shop multiple times with no solution. I discovered that air is getting into the low-pressure side, causing a high-pressure condition that triggers the fans to run excessively. I bleed off the air about every three months, and it fixes the issue temporarily. I showed this to the dealer, but they were clueless and suggested replacing the entire A/C system, at my expense.
Good luck!
I had a similar issue with my 2016 model. I received a high-temperature warning while towing and trying to pass. I discovered a small hole in the thermostat, replaced it with a $30 part from Ford (avoid racing thermostats, as they can trigger the engine light). This didn’t completely solve the problem, as the warning would still appear in hot weather. I then replaced the A/C expansion valve, and now the fan only runs when I start the truck in temperatures over 96°F and shuts off within a minute. Good luck!
Whenever I hear anything about the A/C, I assume it means the system needs to be depressurized, serviced, and then recharged. Is that the situation here? I prefer to avoid having shops work on my vehicles if possible.
Yes and no. You can buy a vacuum pump, gauges, and valve from Amazon for around $170. Replacing the parts is straightforward just 2 bolts and a center stud (there are videos on YouTube), and it took me about 4 hours.
The tricky part is draining the refrigerant. My brother has a recovery pump and tank, but some people vent it to the atmosphere, which is neither healthy nor legal. I’m not one to report, though.
You can recharge the system yourself and purchase refrigerant from Amazon or a local parts store. Some parts stores might even let you use their equipment. If you have some mechanical skills, this job isn’t too difficult.