I just bought a 97 F150 XLT,auto,Triton 4.6 V8, w/113,000 miles. I noticed soon after purchase that after sitting idle (like at a traffic light) for a few min. when trying to take off it has a roaring sound, like there is built up RPM's. As soon as it is driven a block or two, it runs out great. And it seems the longer it sits idle the more it builds up and louder it is at take off.Please, any help anyone can give me would be greatly appreciated. Thanx !

[This message has been edited by R Wood (edited 08-20-2000).]

 

What is the temperature outside? Does it sound like a high pitched whine? I have a 97 F-250 LD with the 4.6 and it does the same thing. The fan clutch engages tighter as the the temperature inside the engine compartment increases to spin the fan faster at low rpm.

 

Thanx for responding. Temp outside is usually around the high 90's here in Alabama.It is more like a roaring sound
( like a rocket getting ready to launch.) I don't know if it's an engine problem or maybe a transmission problem. I haven't noticed any slipping. how long have you had your problem ? Please, anyone, any help at all will be appreciated. Thanx again !

 

It's normal clutch fan operation.

Happens mostly after a strenuous run and immediately stopping and idling. The temperature rises as the cooling system gets rid of the heat. Airflow is low at a stop, so the air flowing thru the radiator is much hotter than normal. This heats up the fan clutch and engages it. When you accelerate, the fan roars. As airflow increases and coolant temperature drops, the clutch disengages and the fan quiets down.

It also happens when you first start the engine for a day and you immediately start driving. Again, normal.

 

It really doesn't get any hard runs, I just bought it last week and it happens when I am just driving normal through town and stopped in traffic for even a little while. Is there something I should do to try and keep the air flow cooler ? Or could the fan clutch be faulty ? I knew an F 150 was the truck I wanted, but I sure didn't know I would run into these problems and worse yet, find out it's suppose to be like this. Any help or suggestions would really be appreciated. Again... Thanx !

 

It's normal fan operation for it to roar when the engine is really hot and the truck is moving slowly, but in your case, I'm beginning to wonder. Under normal around town driving, you shouldn't be hearing it so much. The only time I've ever heard a clutch fan roar while just driving around town was in 100+ degree temps.

I'm just guessing, but I have a feeling something's not right with the clutch fan if I'm understanding what you're saying.

Do you notice if the temperature gauge goes up a bit before the fan clutch engages?

 

I haven't noticed any change in temp. but I will watch it very closely.It has not ran hot at all though. A Ford mech. I had e-mailed before suggested that the viscous fan clutch could be worn out, or a dirty idle air control valve. I will be checking it out tomarrow after work. It doesn't get any hard driving, just cruising around. But I do live in Alabama, and it has been 95 - 102 this last couple weeks. Could that be causing the problem to be more noticeable ? Thanx so much for any help !

 

Hey, mine does the exact same thing as
yours. I had a B/M shiftplus hooked up for
a while and forgot all about it. recently I
unhooked it to put in a chip (it didn't work
like I wanted it to so I took it out.) and when I did the rushing noise came back
, I'm going to hook the shiftplus up again
and I'll let you know what happens. I am
certain this problem went away when I originially put it in ,and if all goes to planned it will go away again. let you know,,,,,98

------------------
98 F-150 4.6 Litre XLT
K/N gen.II fipk
Custom duals w/glasspacks
color matched Snuglid
headlight covers.
doin the monochromatic boogie on the front end.
on the way(headers,air dam,wheels and tires,etc...........................

 

Hey, mine does the exact same thing as
yours. I had a B/M shiftplus hooked up for
a while and forgot all about it. recently I
unhooked it to put in a chip (it didn't work
like I wanted it to so I took it out.) and when I did the rushing noise came back
, I'm going to hook the shiftplus up again
and I'll let you know what happens. I am
certain this problem went away when I originially put it in ,and if all goes to planned it will go away again. let you know,,,,,98

------------------
98 F-150 4.6 Litre XLT
K/N gen.II fipk
Custom duals w/glasspacks
color matched Snuglid
headlight covers.
doin the monochromatic boogie on the front end.
on the way(headers,air dam,wheels and tires,etc...........................

 

YEESSSSSS!!!!!! just as I thought,,the roar
went away when I hooked up the shiftplus
GO buy one ,,quickly! First gear acceleration was also greatly improved.

 

YEESSSSSS!!!!!! just as I thought,,the roar
went away when I hooked up the shiftplus
GO buy one ,,quickly! First gear acceleration was also greatly improved.

 

Sorry,guys don't know why this thing keeps double posting.

 

98SCREAMER,

The double posts happen when you click on the Back button twice on your browser. Essentially, it reposts what you had already posted.

Next time, after posting a message go to the menu at the top of the screen and click on the links for the forum or the Message Board.


[This message has been edited by Dennis (edited 08-22-2000).]