Fan Clutch issue
- Thread starter Ivan5
- Start date
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athensdawgs81
Member
Sounds like it's working as it should. The fan should not run full bore all the time. Especially if the engine has not warmed up. Are your coolant temps good and AC working ok?
twodollars
Full Access Members
Believe that's a pcm controlled clutch, level of engagement controlled by pcm based on coolant temp and ac demand.
bodabdan
Full Access Members
I'm going to go out on a limb and guess that fan clutches are widely misunderstood.
It would be easy to direct bolt a fan to a pulley. Think flex-fans, spacers.... It would move a ton of air but it would use a good bit of power all the time, even when not needed.
The fan clutch is a mechanical means to only spin the fan (engage the fan clutch) when needed, saving fuel and power. It can be engaged by air temperature, a computer, or even air pressure depending on the application.
The end result is the same when everything is working correctly, the fan only engages when it is needed and coasts when not needed.
It would be easy to direct bolt a fan to a pulley. Think flex-fans, spacers.... It would move a ton of air but it would use a good bit of power all the time, even when not needed.
The fan clutch is a mechanical means to only spin the fan (engage the fan clutch) when needed, saving fuel and power. It can be engaged by air temperature, a computer, or even air pressure depending on the application.
The end result is the same when everything is working correctly, the fan only engages when it is needed and coasts when not needed.
https://youtube.com/shorts/7PXvCU0bsME?si=W8Wg8XqKmFSNcHPBHere is a video of it, it’s 100+ degrees outside and the ac pressures are crazy high, 350+ on high 60+ on low
bodabdan
Full Access Members
That looks pretty lazy to me. You should hear it roar if you stab the throttle. Looking slow and having hi a/c pressure point to the same issue, a clutch that's not engaging.
Looking at rock auto I agree with #twodollars, it's electric so either a pcm or fan controller is supposed to be sending it a signal.
Check your wiring and connectors closely, see if you're getting a signal to the clutch, and see if the clutch responds to the correct signal.
Looking at rock auto I agree with #twodollars, it's electric so either a pcm or fan controller is supposed to be sending it a signal.
Check your wiring and connectors closely, see if you're getting a signal to the clutch, and see if the clutch responds to the correct signal.
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athensdawgs81
Member
Unplug the fan clutch under the same conditions and see of it's getting it's 12v signal. If there's 12v then it's likely the fan clutch, if its not then maybe your PCM.
mbtech2003
Full Access Members
Get one off rock auto. Not too bad to replace. Prob just worn out. Or leaking oil. Doesn’t take much for them to not work correctly
Dustin Gebhardt
Full Access Members
How is your AC performing? I had weak AC performance, especially at low vehicle speeds and while idling. I also didn’t see the fan spinning up when the AC pressures went high like your pressure does. I replaced the clutch with a new one (non Motorcraft) but that didn’t fix the issue. I ended up replacing the temperature sensor in the evaporator (behind the glove box). This fixed my tan issue and only for about $20 and 20 minutes of work. Now the fan spins up when the AC pressures climb and my AC vent temperature is back in the 40’s.
