Hey guys. I have a 04 f150 supercrew XLT 4.6L I've been reading on here about how some people think these engines are so quite, so I wanted to go out myself and open the hood and listen for myself to see how quite it really is! That dumb big fan makes all the noise! I can't hear anything over that fan that is always blowing! It seems like it slows down, then stops for just a second and then starts right back up, the fan is kinda loud don't u think? When the fan acually did stop for just one second, I did not hear ANY engine noise what so ever besides a bunch of ticking noise which I have no idea where thats coming from, and a sound like a desial engine which was very minumum.
Is this fan suppose to keep blowing as much as it does? It seems like it's always changing speed from fast to slow to stopping for a second? Why's that anyway? Any info would be great!

 

Come on guys...help me out! lol I need to know if this fan ever shuts off or is there something wrong that it is always on for? I need to know before I take it to the dealer and have them just laugh at me and say it's normal? is it? It's always suppose to be on or what? lol help me!!

 

I agree the fan is very loud. Mine will speed up and slow down every few seconds when the engine is at idle. The speed of the fan is determined by the temperature in the engine bay. The fan hub is coupled to the input shaft with a fluid-filled housing. (Sort of like a torque converter). This fluid has unique properties. As the temperature increases, the viscosity of this fluid INCREASES, causing the fan clutch to slip LESS. This will cause the fan to rotate faster. In reality, the input shaft is spinning the same speed. It's just that the fan clutch is slipping less.

The fan will always turn even when it's not needed, because you won't ever get 100% slip on the fan clutch. The benefit is you do get some fuel savings, because a rigid mount fan would always turn at full engine speed and take more engine power.

When the engine bay is really hot, you'll get full fan speed. See if you notice the next time you're stuck in traffic on a hot day. When you accelerate, you'll hear the fan very loudly, and then it will fade out as the fluid cools down.

Only solution I know for the noise requires replacement of the fan with electrics. There are links to this mod in this forum. After I saw someone else do it, I decided it wasn't worth the hassle.

Hope this helps.

 

Thanks for the reply.....It was very helpful! The engine sounds so nice and smooth, but it's so hard to hear it over the fan, which I was concerned with it being always on, which I take is normal! For you guys that say the engine is so quite, how can you tell over the fan??

 

I don't know how loud or quite the fan or engine is. I barely hear them when I'm driving. I don't usually drive with the hood open and my head out the window trying to "hear" the quiet engine.

 

If you are hearing that much fan noise you should have the fan clutch checked. The fan should spin freely when the engine is cold and off. You can check that yourself. Normal operating speed for the fan should be about the same rpm as the engine would turn at 35mph when you are traveling 60-65mph. In other word the fan should turn about 55% of the engine rpms under normal operating temps.

I've had several fan clutches lock up on me over the years. At 65mph the truck will sound like 747 coming down the highway if the fan clutch locks up.

 

What I did is just have the truck sitting at idial in park open the hood and then was just seeing if I could hear the engine itself but mostly I heard the fan as it goes from very high to very low to stopping for a second then back to spinning again. I don't think anything is wrong with the fan, it's just a big fan that seems like it's always spining in idial, and obviously I can't hear it while I'm driving to hear what it's doing, only when it's sitting in park. Does this sound normal?

 

Sounds to me like it's going bad. Some are fliud drive and some have temp senistive clutch disc's. Either way it shouldn't be grabbing then letting go unless the load/heat factor changes on the engine.

 

It's not bad. I heard other f150 engines on and all you hear off those are the engine fans as well, my orginal question was if they ever shut off or not? Nothing is wrong with the fan, I'm always wonderign why they are always spinning, not just on mine, but every 04 05 f150?

 

I can't answer your question if the fan should always be on, but in reading/researching the discussion on this thread, I think what I've just discovered from my dealer/Ford is worth mentioning. I recently purchased a 07/31/04 F150 FX4 SuperCrew. It was 5 degress out this moring when starting it. I got out to let it warm up and noticed the fan going from low to high/on to off. I didn't think this was normal so I had the dealer run my VIN to see if a related TSB existed. Well, they found what Ford terms a Special Announcement 402000 titled "Engine cooling fan noise at engine startup - described as rolling engine idle noise". The service tech read the entire 'Announcement' and it went on to say Ford is aware of the problem but have yet to find a solution. They also stated replacing the fan clutch did not resolve the problem. Since I don't have the exact text in from of me, it might be worth calling your dealer and having them read or fax the exact statement. I was on another thread attempting to resolve what I call excessive cab noise at 45+ mph. To me, it sounds exactly as if the heat/cool fan is on at high/4. After reading this thread and hearing the 'Special Announcement' I mentoined above, I'm beginning to think it's not wind noise caused by faulty sealing of the front windshield top center (as was believed to be the case on the other thread). Since it sounds just like a fan on high at 45+ mph, I have to believe the fan is on high and stays on high. Perhaps in a general sense this is how the fan works, but since Ford states they have a problem when starting the truck in cold temps with the fan going high/low/on/off, I think the fan operation in general has problems. Any comments? Thanks!

 

Same deal here w/ my 04 Ranger. It can be -20 first thing in the morning and that fan will howl like it is 95 in the shade! It has been like this since day one. Every once in awhile , maybe once every 2 wks. , it will be quiet. It will do the same thing even if it has been in the heated garage ( appro 68 geg.) over night. Have you resolved your problem yet?