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Repair Questions and Answers.

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 #385967  by M-Pressive
 September 27th, 2020, 1:15 pm
I am beyond frustrated with the black car.

I have this chirping sound at 2500 or so RPMs when the car is cold and sits for a day.

From what I can tell it is associated with the alternator belt. I have tried every different level of tension on the belt. It is not as pronounced when the belt is really tight. Like too tight.

I have replaced the belts and pulleys, the alternator as well. If the belt is off the noise does not happen.

I can not get this sound to go away. Video attached.
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 #385968  by M-Pressive
 September 27th, 2020, 1:18 pm
 #385976  by cos1776
 September 27th, 2020, 6:09 pm
Had the same kind of noise on my 99 Ram pickup, would make that noise in the fall/winter when the temp was 30-45 deg on damp mornings for about 5-10 mins. It was the serpentine belt. I replaced everything associated with the belt including the belt. Used belt dressing and it would be fine for about a week and then start again. I also found that a little spritz of Turtle Wax F21 super protectant on the rib side would make it stop for about 2 weeks. I lived with it for about 2 years until I read that a Goodyear Gatorback belt with the crossed hatched ribs was the solution. So I bought one and sure enough it worked, no noise since. Didn't solve a belt noise on my M, but it did on my Ram. Also, I did some checking and it seems that Gatorback belts are now branded Continental Elite. Looks like a #4060528 is the correct one.

John
User avatar
 #385977  by slimpants
 September 28th, 2020, 12:55 am
.

I had essentially the exact same noise/issue with a different (non-300M) vehicle ~ a year ago. After several months trying to ignore it, I happened to be underneath the car fiddling around when my elbow accidently bumped/spun the fan half a rotation. I heard the noise. WT fuh ?!?

Turned out there were a bunch of tiny rocks/gravel trapped (unable to escape) at the bottom of the fan shroud that would bounce around like gd popcorn kernels whenever the fan was running; and the volume/pitch obv increased with RPM. Not unlike your scenario.

Good luck.

8)

.
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 #385979  by In-trepid
 September 28th, 2020, 10:57 am
If I remember correctly, Ryan had a similar problem that he troubleshot for a while and it ended up being the harmonic balancer. Either it was bad, or maybe just not seated correctly. I don't remember These things are always hard to find as they never seem to be the obvious things. It has to be one of five things, the belt, the the alternator or pulley, the power steering pump or pulley, the harmonic balancer, or the tensioner. I couple things I would check would be that the harmonic balancer is seated properly (like take it off completely and reinstall it pulling it on evenly). Also, check that everything looks good with the pieces and the rubber between the two pieces. Make sure it runs perfectly true. I would also remove and reinstall the tensioner (all three bolts) just to make sure that it is seated correctly. Power steering pump is probably the forgotten piece because they never seem to be a problem, but never say never! Good luck.
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 #385983  by LUNAT1C
 September 28th, 2020, 11:57 am
I believe you've already replaced the harmonic balancer (or was that only Ryan?), so if the pulleys all appear to be running smoothly and true to each other, the last piece of the puzzle is the power steering pump, or its pulley. Like John said, that one usually isn't a problem, and I'm not sure how to test it without replacing it. The only reason I replaced my pump was because the accident shattered the pulley, and we didn't want to bother chancing a bent shaft even though it looked fine.
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 #385985  by Sneke_Eyez
 September 28th, 2020, 12:18 pm
In-trepid wrote: September 28th, 2020, 10:57 am If I remember correctly, Ryan had a similar problem that he troubleshot for a while and it ended up being the harmonic balancer. Either it was bad, or maybe just not seated correctly. I don't remember These things are always hard to find as they never seem to be the obvious things. It has to be one of five things, the belt, the the alternator or pulley, the power steering pump or pulley, the harmonic balancer, or the tensioner. I couple things I would check would be that the harmonic balancer is seated properly (like take it off completely and reinstall it pulling it on evenly). Also, check that everything looks good with the pieces and the rubber between the two pieces. Make sure it runs perfectly true. I would also remove and reinstall the tensioner (all three bolts) just to make sure that it is seated correctly. Power steering pump is probably the forgotten piece because they never seem to be a problem, but never say never! Good luck.
You're right, John. This was on the Pro Am and it was a strange belt-related noise.
After replacing the tensioner pulley and the assembly, I ended up replacing the harmonic balancer.
I tried reseating it and it didn't work, so I bought a new one.
It was messing with the belt alignment for the serpentine belt, so even though it looked like it spun true, there had to have been something wrong with it.
Not too long after I did that job, I sold the Pro Am, so I'm not sure what the status is of it now.
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 #385987  by M-Pressive
 September 28th, 2020, 2:26 pm
The balancer was replaced a few weeks ago when I did the water pump.

It appears to be spinning true but I guess I can attempt to take it back off and try and seat it again.

The power steering pulley could be it I guess. The lines into that look really crusty. I hate to open up that can of worms.
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 #385988  by M-Pressive
 September 28th, 2020, 2:34 pm
This sound was happening with the old balancer as well if that helps.
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 #385989  by Sneke_Eyez
 September 28th, 2020, 3:31 pm
Probably not the balancer then... Perhaps the tensioner? Could be the power steering pump I suppose.
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 #385990  by FIREM
 September 28th, 2020, 3:32 pm
Maybe swap the belt with one from a “quiet” car in your fleet. Belts can make strange noises as they flip flop and change direction of the bend around pulleys and idlers.
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 #385992  by monte4
 September 28th, 2020, 6:42 pm
Try rubbing a bar of soap on the underside of your belt. If the sound goes away it's your belt. That's what we did in the old days.
User avatar
 #386020  by M-Pressive
 October 4th, 2020, 7:45 pm
Went with the Continental belt @cos1776 recommended.

All seems good. Drove it today and started it again later and it is quiet.

If it is quiet tomorrow when I go out there I will put it back together and call it fixed.

Thanks for the help everyone!
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