[Ajsimpson15]

2012 Acura MDX with 120k miles, all the regular maintenance done since I bought it. It recently started making a loud whining/whirring upon starting (growing louder while accelerating). We did some research and thought it might be the power steering pump, so we replaced that and the o rings, and it’s still there. The alternator was replaced recently so I’m not sure if that is super relevant, but. Noise is coming from the passenger side of the engine bay.

Video of noise here

Thanks all …..update : after two separate Honda techs listened to it and said it was definitely the power steering pump, we had the tensioner pulley replaced and it fixed everything. Thanks all for your help!

 

[PRGonzalez]

It sounds like the steering pump has air and the fluid is cavitating. I think sounds like low frequency pitch.

1. What work was done with the steering pump?
2. Was it replaced with a new one or refurbished?
3. Have you check all bearings including the serpentine tensioner bearings?
4. Have you done the timing belt and replaced the idle bearings?

Remove the serpentine and do a short engine run of about one minute start without the serpentine belt.
If the noise persists the problem is related to inner parts related to the timing belt.
If the noise is gone, then your problem is related to the outer parts related to the serpentine belt.

 

[somrh1]

It sounds like the steering pump has air and the fluid is cavitating. I think sounds like low frequency pitch.

1. What work was done with the steering pump?
2. Was it replaced with a new one or refurbished?
3. Have you check all bearings including the serpentine tensioner bearings?
4. Have you done the timing belt and replaced the idle bearings?

Remove the serpentine and do a short engine run of about one minute start without the serpentine belt.
If the noise persists the problem is related to inner parts related to the timing belt.
If the noise is gone, then your problem is related to the outer parts related to the serpentine belt.

1. Initially, the o-rings and fluid was changed.
2. Then the pump was replaced with a new one.
3. The pulleys are my next attempt, I haven’t checked or replaced those yet. To be honest, I’m not sure how to just check them.
4. I replaced the timing belt with the water pump about 15-20k ago, I don’t believe it came with an idler pulley.

That’s a good idea. I’ll try that next. Thanks.

 

[somrh1]

It’s also worth mentioning, at no time has there been any bubbles, air or “foam” in the power steering reservoir.

 

[somrh1]

All the pulleys sound fine.

 

[jimhow4545]

Oh yeah that is the sound of PS pump leak, air is getting sucked in at the hose connection, replace the o-ring.

 

[somrh1]

Oh yeah that is the sound of PS pump leak, air is getting sucked in at the hose connection, replace the o-ring.

I replaced the orings. Then replaced the whole Pump with new orings. Where else could it be leaking air, because it’s not there?

 

[jimhow4545]

Did you flush and refilled with new PS fluid? Are you using Honda fluid?
That sound is identical to mine and I fixed by making sure there isn’t any air in the system. Did you turn the steering wheel side to side when flushing and refill?

 

[somrh1]

Did you flush and refilled with new PS fluid? Are you using Honda fluid?
That sound is identical to mine and I fixed by making sure there isn’t any air in the system. Did you turn the steering wheel side to side when flushing and refill?

Swaped orings, then pump, new fluid from Honda twice. Bled it multiple times. No change.

 

[jimhow4545]

Did you check the ps fluid in the reservoir flowing with or without tiny bubble? It should be flowing without any tiny bubbles.

 

[somrh1]

Did you check the ps fluid in the reservoir flowing with or without tiny bubble? It should be flowing without any tiny bubbles.

I did. It’s flowing with no bubbles whatsoever. Is there a filter in the reservoir or return line?

 

[jimhow4545]

started the engine without the serpentine belt and see you still have that noise or not. If you still have noise then it is coming from the timing belt area, bad water pump, idle pulley, oil pump and etc. now you have a time boom.

 

[Ajsimpson15]

started the engine without the serpentine belt and see you still have that noise or not. If you still have noise then it is coming from the timing belt area, bad water pump, idle pulley, oil pump and etc. now you have a time boom.

We pulled off the belt yesterday and started it without. The noise is completely gone with the belt off.

 

[jimhow4545]

We pulled off the belt yesterday and started it without. The noise is completely gone with the belt off.

That is good news. What about AC KOMPRESSOR or the alternator? Or serpentine belt pulley assembly?
If I were you I would be looking to replace the serpentine belt assembly first because it’s easier to replace and a lot cheaper than alternator or ac compressor

 

[jimhow4545]

Also when you turn the wheel left and right (in park) does the noise changes?

 

[qqzj]

Watch this. Could be a bad serpentine belt tensioner

[DIY] A complete guide on diagnosing/fixing noise caused...

My belt area used to generate a weird kind of noise. It is not the common chirp. I am not sure whether it is due to lack of tension or dirty belt. (Belt alignment was not likely the cause. Nobody touched that area when the noise started.) This is how the noise sounds like: It is the same kind...

www.mdxers.org

 

[somrh1]

That is good news. What about AC KOMPRESSOR or the alternator? Or serpentine belt pulley assembly?
If I were you I would be looking to replace the serpentine belt assembly first because it’s easier to replace and a lot cheaper than alternator or ac compressor

I replaced the alternator last week, and both pulleys attached to the tensioner assembly spin freely and smoothly. I haven’t really looked into the AC much because it sounds like it’s coming from much higher up, but I’ll check into that next.

 

[somrh1]

Also when you turn the wheel left and right (in park) does the noise changes?

It does not.

 

[qqzj]

eplaced the alternator last week, and both pulleys attached to the tensioner assembly spin freely and smoothly. I haven’t really looked into the AC much because it sounds like it’s coming from much higher up, but I’ll check into that next.

It is not about these two pulley. It is about the big spring inside the tensioner. It gets weak over time and loses its tension.

 

[jimhow4545]

It is not about these two pulley. It is about the big spring inside the tensioner. It gets weak over time and loses its tension.

Yeah. The whole assembly need to be replaced.