Whine when pressing gas
07-29-2020, 04:56 AM
#1
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Whine when pressing gas
Sound is coming from under the hood near the belts. Whine is in unison with pressing the gas. The harder you press, the louder the whine. What do you think the issue could be?
07-29-2020, 05:56 AM
#2
JK Jedi
I'd put my $5 on a pulley. Given the sound, I kinda think it might be bigger than simple idler or tensioner pulley though. Maybe alternator, power steering, or water pump. I doubt the a/c pulley.
If you have a mechanics stethoscope, makes it easier to pinpoint which one the noise is coming from. If you don't have one, they are a few bucks at any auto store. grab one and probe around as someone steps on the gas as you are doing in the video. obviously be careful as you have the belt turning around.
If you have a mechanics stethoscope, makes it easier to pinpoint which one the noise is coming from. If you don't have one, they are a few bucks at any auto store. grab one and probe around as someone steps on the gas as you are doing in the video. obviously be careful as you have the belt turning around.
Last edited by resharp001; 07-29-2020 at 05:59 AM.
07-29-2020, 07:18 AM
#4
JK Jedi
Would not be surprising. I know bad alternator on some Fords I've had sounds a lot like that now that you mention it. Haven't had bad alternator on jeep yet.
07-29-2020, 08:15 AM
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It’s really difficult to pinpoint the sound, but it’s near the engine/alternator area. Also, just cranked it back up and the noise was there for a few minutes and just stopped...
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08-03-2020, 12:44 PM
#8
Super Moderator
Because it is revving up. Ever heard a Ford pump? They are notorious for that. Pumps go mostly when people think by jamming the steering at the stop they will make the vehicle turn sharper. Makes the relief valve work overtime and poof goes the pump.
Last edited by Sixty4x4; 08-03-2020 at 12:49 PM.
08-04-2020, 05:05 PM
#9
JK Junkie
Looks like a 3.8L, and the serpentine belt comes off in a couple minutes. With the belt off, spin the pulleys and see how they sound and feel. Only spin the PS pump is the normal direction, but if the others spin nicely it's probably the PS pump. A bad PS pump may change sounds when turning the steering wheel.
In lieu of a mechanics stethoscope, a long screwdriver with a hard plastic handle (like an old Craftsman) held to the ear works surprisingly well. One time I diagnosed a lifter-tap down to the exact lifter on a big block Dodge 383 with that method; an individual lifter could be changed via the hole for the pushrod.
In lieu of a mechanics stethoscope, a long screwdriver with a hard plastic handle (like an old Craftsman) held to the ear works surprisingly well. One time I diagnosed a lifter-tap down to the exact lifter on a big block Dodge 383 with that method; an individual lifter could be changed via the hole for the pushrod.