bang coming from engine bay

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bang coming from engine bay

Postby PAZ04U » Tue Dec 21, 2010 10:14 pm

hey guys,

does this happen to anyone else? when giving it a bit of stick, when changing gears from 1st to 2nd and 2nd to 3rd i hear a bang coming from the engine bay sometimes like somthing is hitting the chassis or something. does anyone else get this?

i remember in my mazda 3 mps i had this same problem and it was cause the engine mounts were so soft, is it the same in the libs?

cheers, Alex.
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Re: bang coming from engine bay

Postby subnub » Wed Dec 22, 2010 7:33 am

Was going to say it sounds like engine mounts, have you checked them? I'm not aware of anyone else having these issues so I'd say it's something particular with your car. If it's a fairly solid thud, my money's on the engine mounts.

Other than aftermarket exhausts and FMIC installs that don't have proper clearances or allow for normal engine movement, the other thing I've seen cause banging noises on gearchanges are loose bellhousing bolts, have you had the engine/gearbox out (new clutch for example)?
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Re: bang coming from engine bay

Postby PAZ04U » Wed Dec 22, 2010 9:00 am

No i havent had the engine out fir the clutch or anything like that I'll see if my mechanic and I can see where abdcwhat has been hitting and try and figure it out thanks..
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Re: bang coming from engine bay

Postby jp928 » Thu Dec 23, 2010 7:10 am

On an 08 gtb , surely its a warranty issue for the dealer?
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Re: bang coming from engine bay

Postby cpitts » Mon Jan 31, 2011 5:08 am

I have a similar sound when i cane my lightly modded (but not reflashed) 07 GTB.

This only happened after I openned up the intake and I put it down to running massively rich (also your 50l/100 fuel gauge readings). It's some form of backfiring going on. I can easily get my car to crackle and backfire and that's only with openned up intake and straight through mufflers.

These cars are pigs when their airflow is changed, even slightly. They really need to be reflashed once modded to correct massive over-fuelling that occurs as a compensatory measure.
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Re: bang coming from engine bay

Postby fr250t » Thu Jun 30, 2011 1:29 pm

I'v had my my07 gtb for almost two weeks, only 34000 on the clock, and yer i'v noticed if i rev it out and change too hard there's a hard nock, sounds like the rear dif or somthing ?? (could also be engine mount) but sounds coming from the rear. Doesnt always happen, occasionaly from 1st to 2nd... i thought it was a AWD thing, as i'v never owned one before.
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Re: bang coming from engine bay

Postby Gambit » Thu Jun 30, 2011 2:25 pm

I am getting a similar clanging sound from the mid pipe area, i think its my exhaust hitting the heatshield, which occurs only on deceleration. Though note, it may not be an issue if your running the oem exhaust, rather just something to be aware of.
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Re: bang coming from engine bay

Postby fr250t » Thu Jun 30, 2011 3:33 pm

Yer its the stock exhaust, just got to keep an eye on it, lucky i dont drive it hard often. But would be nice to know if anyone knew what caused it.
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Re: bang coming from engine bay

Postby smythie » Thu Jun 30, 2011 5:53 pm

Mine does the same, at least on the 1st-2nd change. I haven't tried a hard change after that one try.

Unlike cpitts ealier post from the start of the year, mine is definitely something banging into something else - eg driveshaft slapping around, engine/trans moving on their mounts, rear diff moving on its mounts. Some have had the rear diff bushes flog out (haven't checked mine so don't know)
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Re: bang coming from engine bay

Postby jimbo » Thu Jun 30, 2011 6:58 pm

In my first legacy I had a similar problem, banging coming from the engine bay on hard changes. Turned out I had 2 broken engine mounts! :-p
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Re: bang coming from engine bay

Postby cpitts » Thu Jun 30, 2011 8:09 pm

Standard Subaru Diff clunk under hard change.
Had it in my last 2 WRX's and 3 Libby's (including current 07 GTB). You can upgrade the diff mounts/rubbers with nolathane items to stop the movement of the diff under shock loading (i.e.: slamming from 1 to 2)
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Re: bang coming from engine bay

Postby fr250t » Fri Jul 01, 2011 8:38 am

cpitts wrote:Standard Subaru Diff clunk under hard change.
Had it in my last 2 WRX's and 3 Libby's (including current 07 GTB). You can upgrade the diff mounts/rubbers with nolathane items to stop the movement of the diff under shock loading (i.e.: slamming from 1 to 2)


Thanks, i thought it might have been a common thing. If it starts occuring when im not changing hard i will concidering upgrading the mounts, but for now as i said its only 1st to 2nd hard change, ill just take it easy in this gear :P
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Re: bang coming from engine bay

Postby hawks123 » Fri Jul 01, 2011 5:00 pm

Why don't you just not hard change :shock:

I used to do it in the B4 and made a massive thud, but that's cos your not meant to do it and your slowly damaging
the car, imagine the huge amount of force you are putting through it each time you do that.

In the GTB i just give it a tiny bit more time and just a bit of slippage and what do you know - no thud!

Common sense i would have thought.
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Re: bang coming from engine bay

Postby fr250t » Sat Jul 02, 2011 2:21 pm

hawks123 wrote:Why don't you just not hard change :shock:

I used to do it in the B4 and made a massive thud, but that's cos your not meant to do it and your slowly damaging
the car, imagine the huge amount of force you are putting through it each time you do that.

In the GTB i just give it a tiny bit more time and just a bit of slippage and what do you know - no thud!

Common sense i would have thought.


Yer mate understand what your saying, but like i said previously "lucky i dont drive it hard often". I treat my cars with respect, but these cars are racing bread and in the occasional chance i did change hard i noticed this thud and was curious. Appreciate your concern tho ;)
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Re: bang coming from engine bay

Postby Dropz » Sat Jul 16, 2011 10:25 pm

You need to slip the clutch more. Otherwise you'll be up for alot more than a clutch kit when something goes wrong!
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