Cow mooing-like grinding noise(?) !

[MrBars]

Evening all,

My sister drives an 07 mazda 3 sedan (2.0 automatic). The car used to make this noise when we were buying it and the seller had assured us that it was all fixed. The sound didn't make a comeback until the past few days. In fact, it started right after she changed oil + air filter (we've changed oil once already, so should be nothing special).

I am attaching the recording (it's around 8 seconds in). This is happening from dead stop, then accelerating to around 1500 RPM in the first gear.

I found one post about a Mazda MPV that describes a somewhat similar situation (albeit there is no engine light or anything) http://www.mazdaforum.com/forum/mazda-mpv-17/loud-cow-mooing-sound-check-engine-light-8760/

Thanks in advance for any clues!

Audio: (google direct link) https://docs.google.com/open?id=0B1Ntts5qI6saZVpGdi1FalI3Mms

[silverstarmazda]

shit dude...that sounds BAD. ive never heard a mazda 3 make that kind of noise before. hope you can figure it out cuz im stumped

[McGuyver_3]

are you noticing any lag/delay on acceleration?

[Genpu_Mz3]

lol! it literally sounds like a cow, lol! might be your tranny, maybe a mount.

[Cab0oze]

o.O

Have you checked to make sure there is not a mini cow living under your gas pedal...? To me that seems like the likeliest possibility... lol
Good luck and free bump :)

[sudz]

it sounds like it could be something resonating. Is there any Mods to this car? Check to make sure that the Exhaust has all its mounts. Does it do it in neutral when you rev the engine, or just under load (accelerating)

That's pretty loud! (and mildly amusing, i have to admit)

[MrBars]

Thanks for the replies so far :)


are you noticing any lag/delay on acceleration?

Haven't noticed any delay out of the ordinary, interestingly it happens only during VERY gentle acceleration and only in the first gear (or at least that's how we were able to replicate it). At the same time it's proving rather difficult to replicate :(


lol! it literally sounds like a cow, lol! might be your tranny, maybe a mount.

I am hoping it's just a mount!


o.O

Have you checked to make sure there is not a mini cow living under your gas pedal...? To me that seems like the likeliest possibility... lol

I checked and checked, no cow, otherwise we'd have some milk :P


it sounds like it could be something resonating. Is there any Mods to this car? Check to make sure that the Exhaust has all its mounts. Does it do it in neutral when you rev the engine, or just under load (accelerating)

That's pretty loud! (and mildly amusing, i have to admit)

It does sound like something is vibrating/resonating. There are no mods, everything is stock. I will check the exhaust. I was not able to replicate it in neutral while revving. It only happens in the first gear around 1500 rpm, when accelerating from a complete stop (like in the audio, she was standing in the turning lane).


In general, it's also hard to pinpoint where the sound is coming from. When I was able to replicate it, it sounded like it's coming from somewhere in front right area. I did some sharp turning, but yielded no result :(

It seems like the recording muffles the sound a little and that's why it sounds like a cow :) During the actual experience, it almost sounds like a chainsaw (maybe!). :O

I want to try to at least pinpoint the general fault area before going to Jimmy :P

[sudz]

How many KM? could it be a fine chattering of the torque converter? (the automatic's version of the clutch)

Edit: With my extensive automotive experience (practically none, fyi) I'm still leaning on a vibration of exaust system though.

[silverstarmazda]

it might be the exhaust, something loose maybe

[MrBars]

How many KM? could it be a fine chattering of the torque converter? (the automatic's version of the clutch)

Edit: With my extensive automotive experience (practically none, fyi) I'm still leaning on a vibration of exaust system though.

The car is approaching 78k. Both of those observations are valid (also Silverstar's). But does it fit with the fact that it's happening in the first gear at relatively low RPM and maybe at 5-10km/h?

Disclosure: my automotive troubleshooting experience is solely based on forum(s) reading :)

[electricf3el]

this happened to my car recently after an oil change. I could not figure it out until one day my gf got into the car and said "why is there a screwdriver under your hood." Sure enough i popped the hood and in the little tray thing under the hood under the window wipers the mechanic left a srewdriver. she was able to see it through the crack in the hood. The sound disappeared after.

[McGuyver_3]

i find it hard to believe that something is loose because if that would be the case then you would hear the noise more frequently. I have never come across anything like this transmission wise. If it wer related there would be a good chance that you would be able to feel something. As for engine mounts generally they do not make noise when they go. You simply feel a higher amount of vibraions in the car and again it would be more consistant. I would be interested to see/hear this car in person just for kicks. It would be hard to diagnose but at the same time the speeds ar slow enough that with a big enough parking lot you could get someone in the engine bay to listen for the noise.

[silverstarmazda]

possibly timing related?

[MrBars]

Went to Maple Mazda today, they weren't able to replicate it. One thing that was suggested was that a head shield might be loose. Apparently there are more than one?

[silverstarmazda]

Went to Maple Mazda today, they weren't able to replicate it. One thing that was suggested was that a head shield might be loose. Apparently there are more than one?

yes, some of mine fell off LOL. but yea, something like this noise isnt common for our cars. first time im hearing it anyways. your gonna need to find where its coming from, we cant help you over the internet....

flash back* check your transmission fluid. i remembered when i was flushing my transmission fluid and accidentally let it run dry for 1 sec wen the old fluid was pumping out. i think its your torque converter not getting enough fluid. it made a very similar sound to this. and since your accelerating AND turning in the sound clip, its not hard for the fluid to slosh to one side of the pan and let the transmission fluid pick up suck up air for a few seconds. you have to check the transmission fluid while the car is running. the car will run fine even if the transmission fluid is low. thats how i drove to walmart to get more transmission fluid. (as long as it has at least 3 qrts)

and not to bad talk your sister, but you sure she didnt accidentally mistake the transmission drain bolt for the oil drain bolt? ive seen it happen a couple of times, even with expert mechanics