I can't pinpoint this one. Can anyone help? Details in the video description.

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Belt Idler bearing (most likely) water pump bearing or alternator rectifier
it is a little torture test but take the belt off on a cold car and spin each pulley

 

Thanks for your input, doctor J,


I looked at the idler as the engine started (and listened, as well)

Seemed to be spinning freely, and listening with a mechanic's stethoscope did not pinpoint the idler as the culprit.


If it hadn't been in single digits (F.) I would have run the engine without the serpentine belt, maybe this coming weekend.

Tell me more about the noise an alternator rectifier makes, that's a new one on me.

 

This vid has a similar noise (at ~1:30) on a Civic

 

"Quite often you can tell when your bridge rectifier is bad. One sign is that your alternator will make a winning sound, sometimes it's a growling sound, often a bad bridge rectifier will be mistaken for bad bearings".
However, if drive belt surface becomes stiff due to the cold temperature it also can produce similar sound On older cars we could spray belt dressing or even WD-40 to insulate this problem but I would not do this on my Fit as it may create hard to remove mess!

 

OK, thanks for the alternator logic.


The serpentine belt is less than a year/20K miles old.

My trick is to spray water on the belt if I suspect a stiff/noisy belt. No lasting mess. (But I didn't do it 'cause it was too cold that day)


Stay Tuned!

 

Today I did some observations and troubleshooting.


First of all, the engine had been quiet the past few days' cold starts, because it was warmer outside. <SIGH>

So if course there wasn't anything obviously wrong...


I pulled off the part of the heat shield around the bottom of the catalytic converter. (Had removed the upper part last spring) It was holding on at only two of the four mounting points.

There is no shield under the exhaust manifold, just on top (and that one was tight).

Removed the serpentine belt, the idler was quiet and felt smooth when rotated (no pressure on it with belt removed). It had just a barely noticeable end play if I moved it side-to-side. So, it stayed in this time. (If I need one, the local autoparts store has them in stock, hmmm they must fail.)

On re-installation of the serpentine belt, I set the screw-type adjuster one thread looser.


So, we'll see what happens. Not expecting any really cold weather for at least a week here.

 

I had a Chrysler Town and Country that made a similar noise when it was very cold outside. It ended up being the Power Steering Fluid reservoir. On that particular engine, the power steering fluid reservoir had a filter built into it. So as the fluid recirculated, it was getting filtered at the reservoir. Apparently, it's a replacement/maintenance item. Got a different reservoir(that had a clean filter in it) and installed it. The noise went away.


Don't have a clue if our Hondas have something similar.

 

The Fit has electric-assisted steering, and the vid was shot with the car parked (no steering done).

But, thanks.

The noise came back on a recent cold day so I am going to change the serpentine belt idler first ($20) before I have the alternator checked.

 

The alternator should spin freely as well, just a very slight drag from the brushes and should turn smoothly.

 

Well, it's not the serpentine belt idler.

Replaced that today. Note: the Gates brand #38011 idler is a mm or two wider than OEM, so you need to insert a washer to prevent the mounting bolt flange from rubbing on the pulley.

The 'resonance' noise returned when I started the engine. And, it was 60F. in my garage.

The alternator turns free (without the belt on). Still, in the quiet of my garage I think the noise might be coming from there. (Tight bushing maybe?) By the time I hoisted the car to listen underneath, the noise was gone...


Next Step: look for alternator replacement DIYs.

I HATE intermittents.

 

BIG thanks for follow up on the thread. Before changing the alternator try to check it for uniform DC output (some chain store charging system free on-car testing stations can show diode patterns) keep in mind that Honda uses additional device located in fuse box that turn the alternator to the very low output when there is no demand to save fuel (dual charging system , it scared hell out of me when I saw 12 v on accelerating

 

I'm aware of the charging control (CR-V has it, as well).

Still, the noise sounds mechanical to me.

Looking at rebuilt alternators on Rock Auto, I was seeing that they also sold the pulley-side alternator bearings separately. Hmmm. The two they offered had differing outer diameters, though...

I'm not going that route, because my daughter was brought up watching situation comedies where all of life's problems can be resolved in 22 minutes (+ commercials) or less. High expectations! Best to have the whole assy available to pop right in!


++++++++++++++

Found this YouTube vid for an '07, apparently the secret is to remove the EGR valve first and pull the alternator out from the top.

 

Update 3/19/2016:

Installed a Denso alternator (OEM is Mitsubishi). Fairly straightforward job (but MAN! the B+ lead bolt was tight! Hopefully I'll heal without too many scars)

Could feel just a little roughness in the old alternator, not tensioned, out of the car.

The only other external component that could cause this noise might be the A/C compressor clutch...but we will cross that bridge next winter if the noise comes back, I guess.

 

Final follow up



All was quiet during the warm weather, noise did not return. UNTIL


Suddenly the A/C stopped working and the noise was louder and constant. (Still ran OK tho')

No change when A/C switch was engaged. The idle would increase and the rad fans were on, though. No A/C clutch engagement, could not even see it TRY to engage.


Brought the car to an A/C specialist who replaced the compressor. He said the clutch on the OEM unit was shot (better than an imploded unit which would have required more work). Cost was ~$600 USD including labor.

 

Noise that stays with or without clutch engagement comes from the A/C clutch bearing.

 

^^ Right.

The problem that made it difficult to troubleshoot with the initial symptom was that the noise went away too quickly. And, it was REALLY cold then. We never got the chance to turn on A/C last winter while the noise was audible.

 

Hey Buff, so if I'm reading the thread correctly, the issue ended up being the AC compressor clutch? We hit wind chill of -9 F today and I had a whine that increased with engine RPM that didn't go away for the whole 10 minutes I drove (engine did reach operating temp).

 

Our noise lasted ~ 45 seconds on a really cold day.

Once Spring arrived, we didn't hear anything else until the A/C compressor clutch fell apart the following summer.

 

Alright thanks for the details. Maybe it's something else.