98 4.6 vacuum leak? - F150online Forums



98 4.6 vacuum leak?

Reply
 
 
  #1  
Old 12-31-2007, 12:21 PM
Senior Member
Thread Starter
 
Join Date: Dec 2007
Location: Michigan
Posts: 129
Question 98 4.6 vacuum leak?

When I'm at a complete stop and have all accessories turned off there is a loud whining noise coming from the middle of the dash. I'm guessing that it is actually coming from the engine compartment. Has anyone experienced this on their truck? It's a 98 4x4 with the 4.6. Could I have a vaccume leak somewhere and thats what the noise is?? If I put the engine in park is seems to go away but then it comes back when in drive and not moving. When the engine is under load. Any ideas??
Reply With Quote
  #2  
Old 12-31-2007, 11:52 PM
torkum's Avatar
Senior Member
 
Join Date: Dec 2005
Location: MT. JULIET,TN
Posts: 2,423
Possible vacuum leak going to one of the actuators in the dash.
Reply With Quote
  #3  
Old 01-01-2008, 08:22 AM
Technical Article Contributor
 
Join Date: Oct 2005
Location: MI
Posts: 25,637
Turn the selector to "vent". Still here it?

If so - The 98 Vacuum lines plug-in is visible and easy to get at under the dash. if you look in the right spot . Sitting in the driving position about 4" above your right ankle to right is a plug-in with 4 or 5 different colored lines. Check that for leaks.
Reply With Quote
  #4  
Old 02-12-2008, 08:55 PM
Senior Member
Thread Starter
 
Join Date: Dec 2007
Location: Michigan
Posts: 129
Well I took it in to the Ford dealership and they said the noise I'm hearing is normal and that it was coming from the IAC Valve. Normal my A$$. Nothin but crooks!
Reply With Quote
  #5  
Old 02-12-2008, 09:03 PM
Technical Article Contributor
 
Join Date: Oct 2005
Location: MI
Posts: 25,637
Do you have an after market intake? Well , IAC 's do make noises . But you said a "whine" - The don't whine that I know of.. I take that back , they do whine when its colder than sh^t out side lol.

When they do whine in that circumstance, it almost sounds just like a bad power steering pump lol .


Read This -

Bad IAC ???

Last edited by jbrew; 02-12-2008 at 09:11 PM.
Reply With Quote
  #6  
Old 02-12-2008, 09:25 PM
Technical Article Contributor
 
Join Date: Oct 2005
Location: MI
Posts: 25,637
Does the whine sound like this? -

http://s131.photobucket.com/albums/p...nt=snowfun.flv
Reply With Quote
  #7  
Old 02-12-2008, 10:02 PM
Senior Member
Thread Starter
 
Join Date: Dec 2007
Location: Michigan
Posts: 129
No thank god. Mine is more of a whistling sound. Can hear it at a stop light inside the cab, but as soon as I give it gas, it goes away. :o And yes I do have an aftermarket intake.
Reply With Quote
  #8  
Old 02-12-2008, 10:10 PM
Senior Member
 
Join Date: Jan 2007
Location: South Florida
Posts: 317
My 97 had pinhole in the lines that run from the engine to just behind the battery. I found them by keeping the engine running and spraying the lined with a squart bottle. When the sound stopped for a second and returned I looked in that area.
Reply With Quote
  #9  
Old 02-12-2008, 10:47 PM
Technical Article Contributor
 
Join Date: Oct 2005
Location: MI
Posts: 25,637
Quote:
Originally Posted by 98f150guy
No thank god. Mine is more of a whistling sound. Can hear it at a stop light inside the cab, but as soon as I give it gas, it goes away. :o And yes I do have an aftermarket intake.

The dealership said it's the IAC . You do believe them right ?
Reply With Quote
  #10  
Old 02-13-2008, 03:01 PM
Member
 
Join Date: Nov 2007
Location: Over Here
Posts: 89
Quote:
Originally Posted by jbrew
Do you have an after market intake? Well , IAC 's do make noises . But you said a "whine" - The don't whine that I know of.. I take that back , they do whine when its colder than sh^t out side lol.

When they do whine in that circumstance, it almost sounds just like a bad power steering pump lol .


Read This -

Bad IAC ???

Sweeet, I have this noise and I think you are right about that....It only happens when its around 0'f ive noticed.
Reply With Quote
 
 
Reply

Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
cigargod
1997 - 2003 F-150
5
10-05-2015 04:45 AM
bknudsen30
1997 - 2003 F-150
6
09-18-2015 09:56 AM
ThesunIsaw
2009 - 2014 F-150
3
09-11-2015 10:16 PM
ericantonio
Pre-1997 Models
2
09-09-2015 08:59 PM


Thread Tools
Search this Thread

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are Off



All times are GMT -4. The time now is 12:02 AM.