While driving I noticed the general noise from my engine seemed to be increasing over about 1,800 RPM. So today I rev it a little ,with the hood open, and the damn fan is making the noise!

I assume its a clutched fan and at higher RPMs its supposed to disengage?

Could something be going wrong with the clutch?

Truck is '98 4.6

Thanks!

 

absolutly. the fan should disengauge after the engine warms and should only engauge again at lower rpms to cool the engine. Remove and replace it . Tool for it is loaned at auto zone.

 

Mine did the same thing and I replaced the fan clutch. Now I get that noise frequently with the new fan clutch on there. Is there any greasing I need to do before I put it on? I am going to get a new one under warranty tomorrow but I didnt know If i need to grease it prior to going on?

Brian

 

no you do not need to grees it. It should be noted that its normal to hear some sound when the fan clutch is engaged as more air is being moved but other than that it shouldnt make much sound. If the clunch is not replaced there is a chance it could come off and destroy all sorts of things. ie:radiator, shroud,ect.

 

I'm not sure but i think i have the same problem, and so does my mom, the truck is sometimes extremely loud (sounds like a fan noise) but other times (at the same driving conditions) its not so loud, is that similar to what you guys are talking about? my mom has an 04 explorer that does the same thing as my 98 f-150

 

This problem sounds like the IAC is giving you fits.

 

Well I sure would keep an eye on the temp gage and if its getting hot or not reaching normal operating temp better get on it.

 

your fan clutch works on air temp it is puling through the radiator and realy are pretty reliable. They way more often go bad from getting loose bushings than not engaging or stuck engaged. But I guess it could come on early. But RPM will usually make it engage because it pulls more air and if it is warm it heats the clutch locking it up. Also it will engage for a minute after cold start till it gets the oil inside flowing correct.