Fan re-engaging at idle

[RedDakooter05]

Quite sure. RPMs go higher when fan is roaring away. If it dies down in the middle of a gear I can feel it "grab and go". Not shifting but almost like it's a slipping gear that finally engages. Usually I'll try and baby it for the 20 seconds or whatever, but sometimes traffic is coming.

Interesting. Wonder if the clutch is grabbing too hard.

I believe these are electronic controlled, could try unplugging the connector and see how it goes.
The fan will still spin, but shouldn't engage fully.

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[gasmanjohn]

The engine fan can kick on at low speeds to move air across the AC condenser to regulate system pressure. Defrost uses the air conditioning, even if the AC light isn't on, which is usually the cause of the fan coming on at low ambient temps.

This. If I have my climate control set to "Auto" with AC off, even in the 10* Chicago winter, it's using the AC pump occasionally to maintain even cabin temp, defrost/defog windows, etc.

 

[Rp930]

Doesn’t sound normal to me. Should probably be looked at.

 

[Aonarch]

Mine is weird as well.

It is cold out, the engine/ coolant is cold, yet mine fan is on high.

I just figured this is a normal Ford thing.

 

[wdeydwondrer]

So so far we have its normal, it's not normal, and maybe? Lol

 

[erty176]

The engagement and half power is one thing, and that doesn't sound right. The startup after being stopped happens to me since my truck was new, but I notice it doesn't do it if I disable stop start. It's likely part of a brief system check after pulling off from an auto start stop engaged stop. Mine does it during the morning as well, when the vehicle is high idling while warming up, even when it is -10 outside. It may be related to idle speed. Just some thoughts. The half power is concerning, but the times it does it is less so.

 

[SilverSlugger]

So so far we have its normal, it's not normal, and maybe? Lol

Everything seems normal except the loss of power you are bringing up. It's either in your head or something is seriously wrong mechanically. If the truck is running fine, no lights popped up and nothing else..... I would lean to it being more of a placebo situation.

 

[wdeydwondrer]

Everything seems normal except the loss of power you are bringing up. It's either in your head or something is seriously wrong mechanically. If the truck is running fine, no lights popped up and nothing else..... I would lean to it being more of a placebo situation.

Yeah, I don't really have a legit way to test. I suppose just live with it a few more months and see what happens since it's still under warranty.

 

[docarter]

I have never actually noticed the fan engage in 6000 miles of ownership and despite towing with the truck.

 

[Jason B]

The engagement and half power is one thing, and that doesn't sound right. The startup after being stopped happens to me since my truck was new, but I notice it doesn't do it if I disable stop start. It's likely part of a brief system check after pulling off from an auto start stop engaged stop. Mine does it during the morning as well, when the vehicle is high idling while warming up, even when it is -10 outside. It may be related to idle speed. Just some thoughts. The half power is concerning, but the times it does it is less so.

I think you may be onto something. If it is indeed a viscous clutch, then fluid settles to the bottom when the engine is stopped. Once started, it takes a few seconds for the fluid to be circulated.

 

[THLONE]

There are some advantages to being half deef. Turn up the radio.
If a tree falls in the woods and no one is around does it make any noise?

 

[Motorpsychology]

When mine engages it's loud and feels like the engine loses half its go juice until it's done. If that's normal I have no clue how you don't notice lol

I think it is also triggered from the condenser as warm refrigerant enters. The A/C cuts in and out in either A/C or Defrost whether or not the A/C light is on. Sitting at a light may enough to keep the refrigerant from cooling enough and the fan comes on.
Try turning the HVAC completely off and see if it still does it.

I had a Dodge Caravan that hat side-by-side radiator and condenser with twin fans. the condenser fan quit working and the A/C still worked fine as long as you kept above 25mph. As you slowed, it went away until you got back up to speed.

 

[Motorpsychology]

So so far we have its normal, it's not normal, and maybe? Lol

Possibly!

The A/C cycling is the likely source but the AutoStartStop could also have a say.

 

[Motorpsychology]

There are some advantages to being half deef. Turn up the radio.
If a tree falls in the woods and no one is around does it make any noise?

The radio or the tree?

 

[wdeydwondrer]

Possibly!

The A/C cycling is the likely source but the AutoStartStop could also have a say.

I turn my auto ss off, probably going to look into that forscan bit to disable it for good.

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