Sudden increase in RPM cured by depressing pedal?????

I was driving ('97 Explorer) at highway speed when I heard something
under the hood very loudly and very rapidly increase in RPM. My first
thought was the engine had slipped out of drive, but taking my foot
off the accelerator had no effect and the RPM gauge was falling.

When I applied accelerator pressure again, whatever was spinning
rapidly returned to normal.

When next I took my foot off the gas pedal, the same thing repeated. I
applied gas very slightly and the spinning sound returned to normal.

Sounds as if it's coming from under the hood.

Can anyone propose what this might be? - Mike

posible fan clutch
Michael Horowitz wrote:
>I was driving ('97 Explorer) at highway speed when I heard something
>under the hood very loudly and very rapidly increase in RPM. My first
>thought was the engine had slipped out of drive, but taking my foot
>off the accelerator had no effect and the RPM gauge was falling.
>
>When I applied accelerator pressure again, whatever was spinning
>rapidly returned to normal.
>
>When next I took my foot off the gas pedal, the same thing repeated. I
>applied gas very slightly and the spinning sound returned to normal.
>
>Sounds as if it's coming from under the hood.
>
>Can anyone propose what this might be? - Mike

--
Message posted via http://www.carkb.com

What would the relationship be between the fan clutch and the
application of the gas pedal? - Mike


On Sun, 01 Oct 2006 03:29:17 GMT, "state tech via CarKB.com"
<u27177@uwe> wrote:

>posible fan clutch
>Michael Horowitz wrote:
>>I was driving ('97 Explorer) at highway speed when I heard something
>>under the hood very loudly and very rapidly increase in RPM. My first
>>thought was the engine had slipped out of drive, but taking my foot
>>off the accelerator had no effect and the RPM gauge was falling.
>>
>>When I applied accelerator pressure again, whatever was spinning
>>rapidly returned to normal.
>>
>>When next I took my foot off the gas pedal, the same thing repeated. I
>>applied gas very slightly and the spinning sound returned to normal.
>>
>>Sounds as if it's coming from under the hood.
>>
>>Can anyone propose what this might be? - Mike

the change in rpms. it could be on the verge of going bad. see what it feels
like/ engine off & keys in your pocket.

state tech wrote:
>posible fan clutch
>>I was driving ('97 Explorer) at highway speed when I heard something
>>under the hood very loudly and very rapidly increase in RPM. My first
>[quoted text clipped - 10 lines]
>>
>>Can anyone propose what this might be? - Mike

--
Message posted via http://www.carkb.com

Fan does not turn smoothly either when cold or warmed up; should it
spin effortlessly? - MIke


state tech via CarKB.com wrote:
> the change in rpms. it could be on the verge of going bad. see what it feels
> like/ engine off & keys in your pocket.
>
> state tech wrote:
> >posible fan clutch
> >>I was driving ('97 Explorer) at highway speed when I heard something
> >>under the hood very loudly and very rapidly increase in RPM. My first
> >[quoted text clipped - 10 lines]
> >>
> >>Can anyone propose what this might be? - Mike
>
> --
> Message posted via http://www.carkb.com

not totaly effortless. but it should be a free smooth spin. you could spin
the fan off & drive a short distance & listen to see if you still have the
noise. you can remove the fan & clutch assy. and the pulley & belt will still
stay in place. allowing you to test drive.

wrote:
>Fan does not turn smoothly either when cold or warmed up; should it
>spin effortlessly? - MIke
>
>> the change in rpms. it could be on the verge of going bad. see what it feels
>> like/ engine off & keys in your pocket.
>[quoted text clipped - 5 lines]
>> >>
>> >>Can anyone propose what this might be? - Mike

--
Message posted via CarKB.com
http://www.carkb.com/Uwe/Forums.aspx...lorer/200610/1

worn transfer case brought on in part by uneven tire size - Mike


On Wed, 04 Oct 2006 02:50:45 GMT, "state tech via CarKB.com"
<u27177@uwe> wrote:

>not totaly effortless. but it should be a free smooth spin. you could spin
>the fan off & drive a short distance & listen to see if you still have the
>noise. you can remove the fan & clutch assy. and the pulley & belt will still
>stay in place. allowing you to test drive.
>
wrote:
>>Fan does not turn smoothly either when cold or warmed up; should it
>>spin effortlessly? - MIke
>>
>>> the change in rpms. it could be on the verge of going bad. see what it feels
>>> like/ engine off & keys in your pocket.
>>[quoted text clipped - 5 lines]
>>> >>
>>> >>Can anyone propose what this might be? - Mike