05 Liberty 3.7L Rattle/Growl Noise

I have an intermittent rattle/growling noise that only seems to happen at idle or just above idle. Using my automotive stethoscope, it is loudest coming from the power steering pump, and louder yet when the reservoir cap is removed. The noise goes away completely when the serpentine belt is removed.

I replaced the pump and pulley, bled the system, and the noise is still there. I've pulled the valve cover on that side and not seen anything obvious (noise didnt seem to come from inside the valve cover when I ran it with the valve cover removed)

I've also replaced both pulleys on the tensioner and put a new belt on. None of it makes a difference, and the noise isn't affected by turning the wheels, etc.

The noise isn't quite as loud on the alternator, but it could be just a transferred to the power steering pump due to some craziness... Using the stethoscope, none of the other accessories are even close to as loud, so i have no clue what to think.

Here's a youtube of it, listen for the weird intermittent chatter/rattle noise.

http://www.youtube.com/watch?v=gl4p5i4Vst4

Thanks for any input!

That sound is bizarre - never heard that before...

Water pump maybe...?

Bob

I forgot to mention, the sound just about completely goes away when i use a shorter belt and bypass the power steering pump... Instead it has a quieter, different sound that definitely comes from the tensioner (this was before i replaced the pulley on it). It may be due to the tensioner having to be at a completely different angle to get the shorter belt to work though... It doesn't make a sound at all on the stethoscope when everything is routed stock...

So it seems like it just about has to be power steering related, unless the sound is getting transferred from somewhere else

Re power steering pump... You can try this....
Mine was noisy and immediately quietened down using LubeGard Power Steering fluid.
Suction out the power steering reservoir completely, then add 100% LubeGard as below...
40788[/ATTACH]"]
LINK to Read: http://www.lubegard.com/~/C-199/LUBEGARD+Power+Steering+Fluid

Here's some more ridiculousness...


With no belt: No noise at all

With the stock belt routing... Crank -> idler -> tensioner -> ac -> water pump -> alternator -> power steering -> crank
Noise is worst on power steering reservoir, second worst on alternator, everything else sounds normal.

Modified belt routing 1 (shorter belt).... Crank -> idler -> tensioner -> barely touches the ac on it's way to the -> alternator -> water pump -> crank
Noise is mostly gone, though it now rattles clearly in the tensioner pulley

Modified belt routing 2 (stock belt).... crank -> idler -> tensioner -> ac -> alternator -> water pump -> power steering -> crank
Noise is similar to stock, loud on AC clutch and Alternator both, power steering is quieter, but still makes a little noise.


Seems like whatever accessory is in direct line with the alternator (except the water pump) makes the most noise... Trying to find a belt that will let me bypass the alternator and then the AC. I've heard of people claiming their tensioner/idler pulleys were causing noises in other accessories, so I'll investigate this route for the heck of it.

was the pulley on the ps pump replaced?

edit. saw you have a new pulley.

is weird for sure. is the vibration getting transferred down to the rack maybe? bad rack bushings? engine mount?


...also did you replace the entire tensioner as an assembly?

rockymountain said:

was the pulley on the ps pump replaced?

Click to expand...

Yes, I replaced the pulley with a new one when I replaced the pump.

I have a growl/vibration that started when I replaced my tensioner with the Dayco.

My growl shows up when I would rotate my steering wheel to the far ends of its travel, and was worse when the airconditioner was on. The growl became diminished when I changed to a newer belt. You can actually see the tensioner pulley vibrating slightly when a driver rotates the wheel to near full travel.

So you did not replace the tensioner? Just the pulleys? Should of replaced the whole thing
The tensioner will wear out as well and let the belt flop around some, not enough to really see but will

tommudd said:

So you did not replace the tensioner? Just the pulleys? Should of replaced the whole thing
The tensioner will wear out as well and let the belt flop around some, not enough to really see but will

Click to expand...

I agree with Tom. I replaced my serpentine belt tensioner a while ago even though it showed no signs of wear or noise. Everything about it seemed ok visually, pulley spun nice and free, didn't feel rough, tensioner moved nice and freely but replaced it as it was a service item that needed replacing at some mileage I can't quite remember (60k maybe?) and immediately the whole front pulley area was a lot quieter and bizarrely a noise which I assumed was a squawking clutch release bearing went away and a vibration which I had spent ages looking for which felt/sounded like engine mountings disappeared. Seemingly unrelated but the tensioner was the culprit! Maybe that would be a good place to start and is reasonably cheap and if the thing fails it is a tow in job! Keep the old unit as a spare in the Jeep somewhere? Hope this helps, Steve

Or just another thought - Have you spun the alternator (generator) by hand? Is there any noise from it? Also check the decoupler on the end of the alternator (the pulley the belt sits on) if it has one fitted which it looks like it does. It's like a one way clutch designed to give the tensioner an easier life by taking some "belt slap" out. It should spin freely one way and turn the alternator the other way if that makes sense. Is there any noise like a hamsters wheel going round for a few seconds after the engine stops? Thats the alternator freewheel clutch bit - (OAD to give it its proper title Overrunning Alternator Decoupler) If you get someone to turn the engine off while you are under the hood, when everything else stops going round, if you look "inside" the alternator through the gaps just behind the pulley, you will see the alternator stopping a few seconds later. The louder the "hamsters wheel" sound the more worn the alternator bearings or possibly alternator decoupler is. Happy hunting! Steve

Here's what the solution ended up being: Replace Alternator

I replaced the tensioner pulley and belt and had no luck.

So I investigated the alternator belt routing I described above, finally getting a shorter belt to bypass the alternator. That was it! No more noise at all, even the AC compressor which had always been loud is quieted down now to a normal level. So I went and got a new alternator and now everything is back to normal (except now I can hear a little valvetrain noise, but that's another story)

tommudd said:

So you did not replace the tensioner? Just the pulleys? Should of replaced the whole thing
The tensioner will wear out as well and let the belt flop around some, not enough to really see but will

Click to expand...

Replace it ALL,keep the old junk for trail replacement.