Came across a possible solution from Mazda for 1700-2000 rpm Rattling/Buzzing Noise!!

[table5511]

I am going to try this out today. I have not seen this before, so I apologize in advance if this is redundant.

 

[table5511]

I don't think I'm gonna tackle this today because it's colder than ice outside, but I did open the hood and tapped my finger on the metal plate near the plastic clip and sure enough, that sucker rattles like a snake. Another option could be just to insulate this "sandwich" setup between the firewall and the bracket. I'll wait until its warmer outside.

 

[table5511]

I went to Lowes and Ace Hardware today and was unsuccessful in finding a flange nut M8x20. I can't find one on the internet either. My thinking is that the stud is M8x20 and the flange nut is in fact M8 but something other than "20" as M8 is the thread and 20 is the length.... right? screwy.


UPDATE: 5:40pm. I have a vast collection of random hardware fasteners, and I just so happened to have one exact match, the same exact flange nut that is on the Mazda. What are the odds.

I also discovered that the battery hold down bracket flange nuts are the same as the flange nuts on this little firewall bracket, so if anyone ever tries to order these flange nuts, just tell them to order you a "battery hold down bracket flange nut" or "shoulder nut."

 

[ceric]

Great find.
Do you feel the difference, before and after?
Why removing the batter terminal? Is that really necessary? Or, simply a precaution.
What is the proper way to remove the push-on hardness clip?

 

[table5511]

I finally have the flange nut I need, but quite frankly its too darn cold out. I examined the area and think removing the battery is overkill. Should be able to pull the plastic clip off with pliers (which is how I have seen other technicians remove other plastic type clips or retainers) and use a long socket extension to put on the new flange nut. It is supposed to be 50ish mid week so that is likely when I will do it.

I've always had an annoying buzzing almost heat shield type noise around 1900/2000 rpm under load, coming from this exact area so I am confident this is the issue.

 

[table5511]

I went ahead and completed this less than 5 minute project today. There is no need to remove the battery. I could not get the white retainer off with regular pliers, had to use my long 1 foot pliers and twist it clockwise/counter-clockwise while pulling towards me and then it suddenly gave. Be careful not to pull so hard that you stress the wires that the retainer is holding.

This seems to have solved my problem. Went to get groceries, up and down a couple hills. No more rattle/vibration/clacking around 1800-2000 rpm. Seems to have been the metal plate vibrating against the firewall.

Good luck to anyone who tries to find a replacement flange nut.
My advice... take one of the flange nuts off the battery hold down bracket with you into ace hardware and use their bolt/stud template and see if your existing flange nut will screw onto any of them.

Cheers!

 

[ceric]

In fact, I heard about this fix a while back. There was no details. This is the first documented (w/ pictures) info on this vibration issue. Please create a thread under How-To and link to this one. I am someone will need this later.
I will do mine when I have time for it.