Exhaust Blowing Sound (sort of)

[JamesT5]

I'm slightly concerned, I've got a sound coming from the underneath of the car that sounds very much like an exhaust blowing but I don't think it is because it only seems to be on a cold engine and it's not all of the time.

It happens when I give the car some welly (i.e. under boost) and mostly but not exclusively on a cold engine as far as I can tell. I can also feel a vibration or resonance coming up through the car when it happens. When I ease off, let the engine run at a lower rpm for a while it seems to go away and it doesn't happen at idle.

I doubt it's an exhaust blowing because that would be consistent and would happen everytime I revved the engine because either there is or isn't a hole. I wonder if I've got a faulty valve somewhere and whether this is linked in some way to my ETM problem?

Any ideas or experience of this is appreciated!

[merc85]

Cracked exhaust manifold or down pipe flex?

[JamesT5]

Cracked exhaust manifold or down pipe flex?

Thanks Gav, I'm not sure I know what the down pipe flex is or what it does, where it is or how to fix it, that's a new one on me.

Might be worth a trip to ATS on Friday for a free 'safety inspection'.

[JamesT5]

Just Googled 'Down pipe exhaust' and I know what you're on about now Gav. Thanks for the tips, I'll take a look this week, get underneath the car and see if I can spot anything obvious. :B_thumb:

[Jamest5r]

What Gav sats about the mani blowing when its cold is correct, you will have to try and spot it when its cold as when it warms up it expands and seals the gap.

[JamesT5]

What Gav sats about the mani blowing when its cold is correct, you will have to try and spot it when its cold as when it warms up it expands and seals the gap.

What would cause an exhaust manifold to crack in the first place?

[Jamest5r]

What would cause an exhaust manifold to crack in the first place?

Wear and tear mate its been on the road for 14yrs and 200.000+

[JamesT5]

Wear and tear mate its been on the road for 14yrs and 200.000+

12 years and 242,000 miles. You were close..... ;)

[LiamT4]

Same with the exhaust manifold gasket, noisy when cold, but gets quieter when it heats up.

[JamesT5]

I took the car to ATS Euromaster this morning and had 2 fitters go over the exhaust system with a fine tooth comb. They said the exhaust and manifold are fine, there's nothing wrong with it!

:wtf:

Anyway, they said that it could possibly be related to the cone filter moving about and resonating down the exhaust system but that's no guarantee. Basically though, the exhaust system is absolutely fine so at least that's one less thing to worry about. It seems that the sound is a side effect of fitting a cone filter.

:bounce: :beer:

[M-R-P]

Depends on the kind of "blowing" noise you mean but yeah, the cone does make the car sound a fair bit different.

[JamesT5]

Depends on the kind of "blowing" noise you mean but yeah, the cone does make the car sound a fair bit different.

Sounds like I've got a bigger exhaust on which I quite obviously haven't.

[M-R-P]

Yep - the cone will do that :D

[Haizum74]

I have this on mine, sounds like a burbbly fart when cold. Ive just ignored it. If it gets louder then I might consider doing something about it.

[JamesT5]

Yep - the cone will do that :D

I wish you'd said before, you know what I'm like with my car (very paranoid). :D

[M-R-P]

lol. I did warn you of the extra growly-wooshy noises it'll make :D

[JamesT5]

lol. I did warn you of the extra growly-wooshy noises it'll make :D

Yeah, the 'gasp' I was expecting but a raucous exhaust note made me think I had a problem. ;)

[Harvey]

The manifold nuts that are on the head studs do also come loose,and the noise will go away when the engine is hot.

Also not easy to see as there is a heat shield that covers up the manifold - turbo.