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The mkiv Supra Owners Club

Help Diagnosing A Noise...


TheTurtleshead
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Hi Guys….

 

Trying to diagnose a noise on the car that has got me all rattled… Sounds pretty much exactly like the low whirring noise in the video.;

 

http://www.youtube.com/watch?v=-QvfysoyS7M

 

Taking the aux belt off doesn't help, depressing the clutch doesn't help… It sounds like it's coming from the front/centre of the exhaust side cam cover… but it could be travelling. It comes and goes of it's own accord.. Raising the revs a little speeds it up.. raising them more makes it go away.

 

Although I cannot see it wobbling at all, I suspect the cam belt tensioner bearing..

 

Worth mentioning that the engine mounts are facelift and it vibrates a bit when you engage the clutch pulling out of a junction and at idle… I'm wondering if it's amplifying the noise.. The car in the picture appears to be a facelift as well...

 

If anyone has come across this then please don't hesitate to contribute!

 

James

Edited by TheTurtleshead (see edit history)
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I've had a good listen through the trusty AKG K550's and it sounds very familiar. My original silicone filled mounts are shot and the engine shudders badly when garaging but not whilst driving or first thing in the morning. The mounts must soften as they heat up and allow freer movement which then amplifies any existing noises as they are too solid to absorb vibration effectively......

 

Which leads me on to the possible cause; If it's anything like mine, you may have a slight turbo heat shield vibration. My car makes this noise and the shield rattles at idle because of the bad mounts. It also sounds like a bearing howl but not in a rough, scratchy way though. The timing belt idler pulley bearing is a good suspect as you say, as could be the timing belt covers.

 

I really think it's a turbo shield or other cover or thin metal part, maybe even an induction howl. Try squeezing the various induction hoses and also operating the throttle from under the bonnet to find the harmonic sweet spot, (if there is one), further up the rev' range.

 

Can you do a video with the camera right in close to the various nooks and crannies with a tiny wee bit of throttle?

 

A mechanic's stethoscope might also pinpoint it. ;)

 

After another listen and realising, (I think?), that it wasn't your video, it does get much louder when you/he/they lean/s toward the turbos and iirc mine sounds like an airflow related issue through that area that I think peaks and dies off as I increase throttle too.

 

I think!

Edited by Morpheus
I used to be confused but now I just don't know. (see edit history)
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You can hear it a bit here as well(starts around 34 seconds)…. although this guy's engine sounds a lot more rattle'y than mine…

 

 

Yeah it's not my video… just the same noise.. Car pulls and cruises perfectly… engine is smooth and sweet with just the quiet ticking of injectors to accompany this f'cking noise!! :( I'll have a good investigate at the weekend…. hopefully it's nothing.

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