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I have a 2002 Stratus sedan with the 2.7L V6 and am trying to diagnose a new whining noise under the hood. The car has 112,000 miles on it and has had regular oil changes every 4,000 to 5,000 miles.It changes directly with the engine speed getting louder at higher rpm's at constant speeds or under acceleration loads. When coasting down the volume will decrease. The sound seems to come from the passenger side, accessory drive end of the engine. Initially I thought it was the alternator bearings. I pulled the alternator and it's bearings felt fine. It checked out fine and was quiet when tested at the local parts store. Before hooking up the drive belt at re-installation, i ran the engine briefly and the noise was still there so I believe the A/C compressor and alternator are not the cause. The sound doesn't change when turning the steering wheel so I'm fairly sure it's not the power steering pump.The sound doesn't seem to be coming from the back side of the engine but more up top. It also seems to carry through the plastic intake manifold. I don't seem to be loosing coolant and have not found anything on the oil dipstick. I hope to pull the splash shield this weekend to get a better look at the weep hole to check for leakage at it. I'm thinking that I might have a water pump going. Does any one know of a way to check from the outside or some hints to narrow down the source of the sound ? I'd appreciate any advice.
 

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If you had the serpentine belt off and the noise was still there, it sounds like an internal engine noise. A whine is unusual for a chain-driven water pump as they usually growl or rattle. Any 'ck engine' light or vacuum leaks? It is possible for the timing chain itself or crankshaft-driven oil pump to whine.
If a chain guide has worn, the links could make a whine as they 'whizz' over the bare or broken spot on the guide. An oil pump sucking air or a restricted intake screen could make the oil pump whine.
The only real visual access would be to pull the upper intake manifold and a valve cover to look down inside for anything unusual like heavy sludge build-up or bits of metal. At that point you may have to decide if the rest of the car is worth a reman engine or engine rebuild.
If you have the tools, space and know-how to do the work yourself that would be a plus, but I'm getting a little ahead of myself here. Investigation, diagnosis and assessment always come first. A good service manual with 2.7L repair information would help for now.
 

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This sounds like the power steering pump. If you only took off the serpentine belt there is one more belt that drives the power steering pump. The pump is on the back side of the engine on top. My 02 stratus had this whine issue and while everything worked well, it also made a whiring and grinding noise and then i knew it was time to replace that. Took care of most of the noise when i did. Just a thought to maybe check that and pull that belt off too. The interesting thing is i had trouble with all the accessories on that car, all made grinding noises, ac compressor, alternator and then the power steering pump. Amazing how much noise and vibration each can make when they are ready to go out.
 

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Discussion Starter #5
No check engine lights or known vacuum leaks. I had gone through the vacuum lines last summer looking for the leaks that were causing an evap system code. other than the noise, everything seems to be functioning fine. I'll pull the power steering pump belt when I pull the splash shield and give another look around. That'll give me another 'listening' perspective.Thanks for the suggestions. I'll be back when I know more.
 

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Well, this whole thing took a turn I didn't expect. First I pulled the AC/alternator belt and the power steering pump belt and started the engine up. It actually sounded pretty quiet without the whining sound I was chasing. I thought that was good news. Next I added the power steering belt on. It did produce a little noise but not the whining or at the volume I had been hearing. Adding the AC/alternator belt didn't seem to increase the noise. Then I tried each belt individually. Again, no real difference between the two. Here's where I went to get a second set of ears. My wife had also driven the care and commented on the noise even though I hadn't mentioned it to her. Her ears gave the same response. No belts was a little quieter than either or both belts but, not the sound we had heard. Right now I'm stumped. I drove it 40 miles today in my daily commute and didn't hear the whine that was there last week. I'll continue to drive and listen. I can't believe removing and re-installing the belts would make it go away. It sure didn't sound like belt noise to me.
 

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Well maybe not a belt noise per se, but one of the belt driven accessories making noise. By ruling those out, we can isolate the noise source. We want to rule out an internal engine noise first.
There is a filter mesh screen in the P/S reservoir that, if plugging up can make a whine that isn't dependent on turning the wheel (load). It would be more constant and rise and fall in pitch with engine speed. Wrong or worn P/S fluid can also make it noisy.
 

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Is that screen something that can be taken out and cleaned ? I'll need to go look for it. Another thought I had was that had been in the 40's this past weekend when things were quiet. The temperatures were colder when I heard. It's supposed to be in the teens tonight so if temperature is a contributor, maybe it'll come back (I can't believe that I'm hoping it returns !). I suppose changing the fluid is worth a try too.
 

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The cold weather did not bring the noise back. I'll dig more into changing the fluid and finding and cleaning the screen you mentioned. Thanks.
 

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It took a couple months but the noise finally got consistent and worse. The a/c clutch bearing went. Replaced it today and things were much quieter on a test drive. We'll drive it for a few days and see how it goes. NAPA was the only place that I could find a replacement bearing. My compressor is a Sanden model # 4975. The bearing was 50mm OD x 35mm ID x 20mm wide. Other auto parts stores had bearings listed that were off a couple of mm's in one dimension or another.
 

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Thanks for the update and glad that you found a bearing. Many Sanden compressors are serviced by assembly replacement only, the clutch isn't available separately.
The A/C clutch bearing only spins when the A/C is clutch is disengaged, so the noise should only have happened when the A/C or defrost was off?
 

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I was not able to find a service clutch anywhere. Everyone had the whole compressor. Feeling kinda' lucky that the bearing was available and not hard to swap out. On my compressor the bearing always spins. The bearing inner race and clutch coil are
wrapped around a 35mm dia. stub of the compressor housing. The compressor shaft runs through the middle to attach to the clutch plate. When the clutch engages, it locks onto the face of the pulley to drive the compressor shaft.
 
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