Jeep JL 3.6 Engine Whine After Serpentine Belt Replacement

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djowen6565

Member
Hey Everyone! Glad to be here. Not new to the scene, just to the forum.

I recently hit 95k miles on my 2018 JLUR 3.6 and have been tackling the 100k maintenance items. Everything has been going great and the Jeep is definitely appreciating the spa days...

I noticed a few days after replacing my serpentine belt and lubing up all the pulley bearings that I have developed an RPM-dependent whine. Sounds very much like a traditional power steering pump (but we don't have those lol). I'm leaning toward the water pump bearing not liking the new tension but wanted to see if you all had any other suggestions.

Whine happens under acceleration (not idle), is RPM dependent, and happens when revving in neutral. It's not super noticeable right now, but I'm not one to wait until things break, especially considering how far off the beaten path I tend to go.

Thanks for the help!

-Dave
 
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jeeeep

jeeeep

Hooked
agree water pump but I would also check the alternator pully.

do you have someone that can rev it up while you listen closer?
 
RJV

RJV

Member
What brand belt and what brand tensioner? I haven't done my JL yet, but I know on my KJ there's two different pulley size options on the tensioners and two slightly different belt sizes to match and if you mismatch you can have issues - usually buy the belt and tensioner from the same brand.
 
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djowen6565

Member
Hey guys, I have a water pump, tensioner, and all new idlers coming next weekend. So I’ll update you all on the outcome.

The belt was a Napa belt, not sure of the manufacturer. the belt in their system is wrong, so we had to find one manually… and did. Went on without an issue.

When I have the new components, I’ll check the alternator pulley. I really don’t think (and hope) that’s not it.
 
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isiahdavis

New member
djowen6565 said:
Hey Everyone! Glad to be here. Not new to the scene, just to the forum.

I recently hit 95k miles on my 2018 JLUR 3.6 and have been tackling the 100k maintenance items. Everything has been going great and the Jeep is definitely appreciating the spa days...

I noticed a few days after replacing my serpentine belt and lubing up all the pulley bearings that I have developed an RPM-dependent whine. Sounds very much like a traditional power steering pump (but we don't have those lol). I'm leaning toward the water pump bearing not liking the new tension but wanted to see if you all had any other suggestions.

Whine happens under acceleration (not idle), is RPM dependent, and happens when revving in neutral. It's not super noticeable right now, but I'm not one to wait until things break, especially considering how far off the beaten path I tend to go.

Thanks for the help!

-Dave
Click to expand...
If a newly installed serpentine belt is making noise, it is a sign of a problem within the engine's front end drive system. Serpentine belt noise is the equivalent to a “check engine” light that indicates something is wrong with the belt drive system.
 
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djowen6565

Member
isiahdavis said:
If a newly installed serpentine belt is making noise, it is a sign of a problem within the engine's front end drive system. Serpentine belt noise is the equivalent to a “check engine” light that indicates something is wrong with the belt drive system.
Click to expand...
couldn’t have been reiterated any more eloquently.
 
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OverlanderJK

OverlanderJK

Resident Smartass
isiahdavis said:
If a newly installed serpentine belt is making noise, it is a sign of a problem within the engine's front end drive system. Serpentine belt noise is the equivalent to a “check engine” light that indicates something is wrong with the belt drive system.
Click to expand...
That’s great but why the hyperlink?
 
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djowen6565

Member
OverlanderJK said:
That’s great but why the hyperlink?
Click to expand...
Just a theory, but it seems like a plug for Westbury Jeep Chrysler Dodge Ram Service & Parts which is running the website he linked and happens to be in the same general location as the poster…

I broke the link in my reply to him, as well. 😏
 
D

djowen6565

Member
djowen6565 said:
Hey guys, I have a water pump, tensioner, and all new idlers coming next weekend. So I’ll update you all on the outcome.

The belt was a Napa belt, not sure of the manufacturer. the belt in their system is wrong, so we had to find one manually… and did. Went on without an issue.

When I have the new components, I’ll check the alternator pulley. I really don’t think (and hope) that’s not it.
Click to expand...
Definitely the water pump. All is quiet now, I noticed an odd chirp sound when the alternator free wheels, but not when you spin it in its normal direction. Anyone knows of a way to grease/oil whatever bearing is in the actual pulley? It’s not the alternator shaft bearings, it’s whatever allows the pulley to free wheel.

Squeaky Alternator Pulley
 
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