engine noise - 2002 3.7

[jeeptorino68]

The alternator and a.c. spin great, no play. The power steering is harder to tell because it wants to pump fluid when you spin it...the ps pump was replaced by me about 6 months ago. I think I got a reman unit from oreilly. The harmonic balancer is solid (can grab it and pull or shake any direction and it moves the whole jeep)
So they all seem normal. No noises or chunkyness when you turn them...

 

[jeeptorino68]

cut a notch at the bottom of the shroud and you'll be good.
best mod I ever did.

I did this. Best modification I have ever done. Details on this to come later.

here is a how to on doing this mod. in case anyone in the future is looking to do it.
easy.
worth it.
http://www.jeepkj.com/forum/f202/hd-fan-shroud-mod-quick-removal-59988/#post685072

 

[Conundrum2006]

More endless information. Noise is there with or without the clutch fan. Noise is there after replacing the tensioner and both of its idler pulleys (gates brand) I can't seem to pinpoint it to any other pulley or device. Power steering, alternator, ac, balancer, water pump.
Any culprits more likely than another? The alternator I suspect has been replaced by the PO. The pulley has marks on it from being messed with. And it is denso which I don't think would be factory is that correct?

Alternator, can be pretty noisy. So can a water pump.

Saying denso most likely is oem, usually rebuilders/remanufactures will paint it and put their sticker on it, but the denso numbers should be visible some place on the unit.

When I swapped out our 3.7, I put a new alternator and water pump, same compressor, idler pulley, and power steering pump the noise was greatly reduced from the belt drive area.

But I'd test with a stethoscope while running, alt and compressor are right on top, even power steering(?) are accessible.
Unless it is very bad turning by hand may not cause the sound.

Not sure what your sound is like, IMO alternator and compressor are the more likely to be noisy.

 

[Conundrum2006]

Btw might have missed this did you try running the engine briefly with out the belt ?
Can't do it for very long, as long as the engine is cool it should be fine for a few min.

If the sound is not there you've eliminated everything in the belt drive as the source.

The other noise I thought of is compressor engaging. Ours in on a 2006 commander and pretty noisy for a few seconds then quiets down.


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[jeeptorino68]

Thanks for the ideas, no noise without the belt, that is why I am down to pulleys in that system. The noise occurs with or without the a.c. engaged

 

[uss2defiant]

the pulley's all sounded good with the stethoscope?
https://www.youtube.com/watch?v=LARu9aMkUIo

 

[jeeptorino68]

They did to me...but that video will help. I will check again

 

[uss2defiant]

maybe it's the HVAC blower fan?

 

[Conundrum2006]

maybe it's the HVAC blower fan?

Very true. I thought there was a engine problem final noticed it went away when the fan was off.

 

[jeeptorino68]

Worth a shot. I will look tonight

 

[jeeptorino68]

the pulley's all sounded good with the stethoscope?
https://www.youtube.com/watch?v=LARu9aMkUIo

Thanks for the video link, but my pulleys all sound better than that...might be the a.c....but I am not very sure. When the noise occurs it seems like it hits through everything...
Also not the hvac fan

 

[uss2defiant]

not the compressor kicking in and out I take it?

did you say you test drove it without the clutch fan?

 

[jeeptorino68]

Yea nothing to do with the compressor turning on and off. Yes ran it without the clutch fan on the jeep. Same sounds.

 

[jeeptorino68]

Here is a YouTube of the noise. Pay attention around 40 seconds you can hear it best there...

https://youtu.be/OoiJkMMrRaU

 

[Conundrum2006]

Ok. What a odd sound . Put head phones on too listen. It really sounds deeper then drive belt and accessories. And it only makes this sound when running with the belt on? I'd almost want to check the other side of it and see if the flex plate and torque converter bolts are ok. I'd be surprised if this was say the water pump.

Almost like something clunking on the under carriage or in the motor.
I'm thinking stuff like catalytic converter . Hard lines banging maybe, it doesn't sound in rhythm with the motor, more like a vibration. It is like it drops some Morris code then everything is normal for 10 seconds then it comes back. wouldn't suspect alternator or compressor first lets see what someone more knowledgeable has to say.


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[jeeptorino68]

it is very strange isnt it, but yes nothing with the serpentine belt disconnected.
it comes and it goes, doesnt seem dependent on load, speed, etc.

 

[Conundrum2006]

Did it do this before the power steering pump was replaced?

Btw very clean engine bay. Everything looks good so it's hard for me to trust a gut instinct on how something has worn. It looks like the 2012 engine I put in everything but my ac compressor looking the business.


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[jeeptorino68]

No, nothing like this before the power steering pump was replaced. I am wondering about it more now...it is a reman unit with lifetime warranty, but not a fun one to replace...but I wonder if that is it?

Thanks on the engine bay too. Things are more pleasant to work on when clean. Its amazing what a spray down with simple green or 409 and a rinse will do. I do this with each oil change.

 

[uss2defiant]

oh wow.
this is beyond me.
hopefully tjkj or tom can comment.

 

[teeje]

Just to be sure, no noise without the belt right? Sounds like a bad ps pump. It may be something you can't see or feel, but I think that is your issue


2002 Jeep Liberty 3.7L with brand new engine
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