High Pitched Whistle Coming from Engine in Cold Weather?
#226
Reviving an older thread here.....
I have this issue with my truck, however it's not just in cold weather, it's year round.
About 1800-1900 rpm I get a whistle under the hood, in cold weather it's very high pitched, in warm weather it's more of a drone.
Here's the kicker, when I run cruise control, the noise goes away.
Anyone got any ideas?
Any chance this could be a IAC valve problem?
I have this issue with my truck, however it's not just in cold weather, it's year round.
About 1800-1900 rpm I get a whistle under the hood, in cold weather it's very high pitched, in warm weather it's more of a drone.
Here's the kicker, when I run cruise control, the noise goes away.
Anyone got any ideas?
Any chance this could be a IAC valve problem?
Last edited by jntibs; 07-29-2010 at 06:41 PM.
#229
Gentlemen,
I have 04, f150 Same issues (4.6L). I am almost positive its the alternator. Like other have said happens when about 0 degs out or colder, lasts about 10 seconds. It will last a little longer if its really cold(up to 30 seconds).
Now the second issue the one at 1800-1900 rpm range i have as well. I believe its feedback from the alternator into the electrical system through the speakers. They have special diodes that prevent this from happening and cause increased ripple voltage(if they fail). The part that does not make sense is this rpm noise feedback only happens when its cold in the winter which may bust my diode failure theory. I swear the noise comes through the speakers not the engine bay. (different that the noise at initial startup when cold)
This weekend im going to swap out my belt and while its off going to give my alternator a spin and check things out. (I will replace my alternator if i hear slight grinding or odd bearing noise).
Side note for the worse mileage in winter issue. In addition to the reasons stated above, when its cold the transmission delays shifting into overdrive too keep the RPMS up to heat up the tranny (fluid friction in the torque converter) this decreases mileage. Happens every winter to me.
I'll follow up next week on the status though its not cold enough to officially confirm this fix yet.
Later,
I have 04, f150 Same issues (4.6L). I am almost positive its the alternator. Like other have said happens when about 0 degs out or colder, lasts about 10 seconds. It will last a little longer if its really cold(up to 30 seconds).
Now the second issue the one at 1800-1900 rpm range i have as well. I believe its feedback from the alternator into the electrical system through the speakers. They have special diodes that prevent this from happening and cause increased ripple voltage(if they fail). The part that does not make sense is this rpm noise feedback only happens when its cold in the winter which may bust my diode failure theory. I swear the noise comes through the speakers not the engine bay. (different that the noise at initial startup when cold)
This weekend im going to swap out my belt and while its off going to give my alternator a spin and check things out. (I will replace my alternator if i hear slight grinding or odd bearing noise).
Side note for the worse mileage in winter issue. In addition to the reasons stated above, when its cold the transmission delays shifting into overdrive too keep the RPMS up to heat up the tranny (fluid friction in the torque converter) this decreases mileage. Happens every winter to me.
I'll follow up next week on the status though its not cold enough to officially confirm this fix yet.
Later,
#231
#232
#233
LOL, I'm 5 years late to the party. I've had this noise since the truck was new 5 years ago. My magic temp used to be 7 degrees, now it's up to 20 so it's been doing it more lately it seems.
An audio of the exact sound (from another guys truck) is posted at #166 in this thread.
https://www.f150online.com/forums/3543175-post166.html
The TSB link and fix for this problem is located at post #180
https://www.f150online.com/forums/3557647-post180.html
It seems now that anyone with any type of whine, whistle, whoot, or noise is posting in this thread.
Paul
An audio of the exact sound (from another guys truck) is posted at #166 in this thread.
https://www.f150online.com/forums/3543175-post166.html
The TSB link and fix for this problem is located at post #180
https://www.f150online.com/forums/3557647-post180.html
It seems now that anyone with any type of whine, whistle, whoot, or noise is posting in this thread.
Paul
Last edited by Paul2; 12-20-2010 at 01:53 PM.
#234
My truck has experienced the annoying cold weather high pitched whistle since new. I can't go another winter listening to this whistle and just ordered an alternator and new belt. Going to throw on a new fan clutch as well. Hopefully, I will catch the culprit with these changes!
#235
I have had it in very cold weather since I bought the truck new and just the other day it happened again. My radio was on and I just reached over and pushed the **** off to listen better. When the radio went off so did the whistle at the exact same time. So like someone stated above I believe it is some type of altenator whine and it comes through the speakers.
#236
#237
I have had it in very cold weather since I bought the truck new and just the other day it happened again. My radio was on and I just reached over and pushed the **** off to listen better. When the radio went off so did the whistle at the exact same time. So like someone stated above I believe it is some type of altenator whine and it comes through the speakers.
#238
#240