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Problem in the rear of my X?

Posted: Sun Dec 02, 2012 6:37 pm
by Slash
Drove my car for 45minutes to the city last night, just cruising, nothing silly... just as I was looking for a park, I a weird noise, but didn't think it was from my car.
I parked and switched the car off, the noise was still there and coming from the back of my car.
[youtube]http://www.youtube.com/watch?v=FyvVoaZpUrU&feature=plcp[/youtube]
Anyone have any idea what it is?

It stopped a few minutes later and hasn't happened again since.

Posted: Sun Dec 02, 2012 7:05 pm
by SAM-24A
That sounds Horrible .... But that doesn't necessarily mean it's bad.

The vehicle was obviously stationary, so that discounts any rotating parts that might be seizing under load etc.

I'm guessing that sound was occurring while the engine was at idle and more obvious toward the rear of the car.

I'm leaning toward partial Internal Catalytic Substrate "Collapse or Blockage".
It sounds much like Exhaust Pressure being restricted (the squealing sound) followed by a Pressure Release Sound (the swish/phuuuu sound) once the pressure has increased enough to push through (released)

You may have damaged you Catalytic Converter (hit something on the road) which has loosened/shaken the Internal Substrate.

If you have the original OEM Cat (I'm thinking it's a Ceramic Substrate - Crimped/Pressed in place)
These Ceramic Substrate Cats can experience Internal Failure because the Substrate will Collapse like a Crushed Biscuit when damaged via an external cause.

That's why most Performance/Aftermarket Cats are made with Stainless Steel Substrates (welded in place) which don't collapse like the Ceramic Type.

It's Definitely a Weird Sound .... but that's my Analysis ..... I might Very Well Wrong thou.
Check your Cat for external damage Sachin ....



Sam ..... *thumb*
Merlinised MIVEC - AspiRe 2.4L
Merlin Inspired Variable Engine Control

Posted: Sun Dec 02, 2012 7:10 pm
by SAM-24A
Alternate Analysis:

Turbo Rotation/UICP/Intercoller Leakage/Restriction at Idle ..... transmitting the sound down & through the exhaust.

Check all your Piping Clamps/Connectors at the Silicone Joints for Leaks.

Might also be a Malfunctioning BOV .... releasing pressure Prematurely.





Sam ..... *thumb*
Merlinised MIVEC - AspiRe 2.4L
Merlin Inspired Variable Engine Control

Posted: Sun Dec 02, 2012 7:51 pm
by Slash
It started as I was looking for a park.. but the video is with the car switched off...

Posted: Sun Dec 02, 2012 8:10 pm
by Tweak
not the awc pump going nuts?

Posted: Sun Dec 02, 2012 8:14 pm
by Slash
Nope all off...
O thought it was the pump.. but I expected it to stop when I turned the car off.. it didnt..

Posted: Sun Dec 02, 2012 8:16 pm
by SAM-24A
Switched Off ..... WTF ..... Gremlins .... :twisted:

How long did this sound last for .... ?

Now I have no idea .... *noidea*




Sam ..... *thumb*
Merlinised MIVEC - AspiRe 2.4L
Merlin Inspired Variable Engine Control

Posted: Sun Dec 02, 2012 8:22 pm
by SAM-24A
Sounds like your EVO is possessed by the Devil .... :twisted:

Quick Sachin .... Sell It .... before it's to late .... *sad*

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I'll take it off your hands ..... *rolleyes*


Sam ..... *thumb*
Merlinised MIVEC - AspiRe 2.4L
Merlin Inspired Variable Engine Control

Posted: Sun Dec 02, 2012 8:31 pm
by Frosty
Just throwing this out there, I had something very similar a while ago after I drove mine very hard on a coolish day, and not for very long (naughty).
I deduced it was hot gases in the exhaust system condensing and 'boiling' as such on the super heated pipes in the system; then converted back to a gas, re-condensing, etc. This sound is then amplified due to the design of an exhaust.

I could be very wrong, but it's food for thought.

Posted: Sun Dec 02, 2012 8:31 pm
by Slash
It was a few minutes after I first heard it before I took the video.. It lasted a few more minutes after I took it..

I moved the car from Hall 3 to Hall 2 (Convention center) about 15 minutes later.. no more sound.. and hasn't happened since..

Posted: Sun Dec 02, 2012 8:35 pm
by Slash
Frosty wrote:Just throwing this out there, I had something very similar a while ago after I drove mine very hard on a coolish day, and not for very long (naughty). I deduced it was hot gases in the exhaust system condensing and boiling as such on the super heated pipes in the system; then converted back to a gas, re-condensing, etc. This sound is then amplified due to the design of an exhaust. I could be very wrong, but its food for thought.


I cruised into the city (approximately 35km).. did nothing silly or naughty.. But the out side temp was pushing 40 degs.. inside the car park was much cooler and I was crusing for a space when the noise started...

Posted: Sun Dec 02, 2012 8:37 pm
by tencents
look at botto right qtr of screen @ around 4-6 sec.. is that something blowing out or just a glare off the camera?

Posted: Sun Dec 02, 2012 8:40 pm
by Slash
glare.. there is nothing capable of blowing out in that direction..