noise from under the bonnet!!! HELP

[billgatese30]

help

there is a noise coming from under the bonnet, it sounds like an air leak from somewhere but i have had no luck finding out whereabouts it is coming from so far???

it is a constant sound like there is a leak in a pressurised air hose, there is no liquid leaks from anywhere and i can't see where its coming from(bit of paper is not blowing around when placed next to any hose joints/connections etc)

any help would be very very much appriciated.

thanks in advance

[jonbuoy]

It is a common noise heard from the Idle Control Valve, nothing to worry about. If u can sometimes hear it get louder or sound faster then that is what it is. I have same thing with mine and it either needs cleanin or replacing, i cleaned mine and it made that noise ever since. U can also experience bad idle speed aswell which is caused by the Idle Control Valve. Hope that helps? Jon

[Adammcf]

I had a loud hissing noise coming from my engine. It was coming from the number 6 inlet manifold by the inlet closest to the bulkhead.
Hopefully when I put the head back on with a new gasket and studs etc it should cure it.

[billgatese30]

has nobaody else got any ideas

[Borderbmw]

Is it a constant hissing or does it come and go?

[dazleeds]

u havent been messin with the fan have you???
i bent mine very slightly and that makes a weird hissin when you rev now

borderbmw you got cent lock sorted yet mate?? Daz leeds

[Karan]

has nobaody else got any ideas

with the engine running...... spray carb cleaner around intake areas ...small areas a a time.... if u hear a change in not of engine..... u have found the leak! check where it meets the head, tb area, airbox trunking to inlent manifold, also may be water pump bearing, PAS pump bearing, not much else i can think of..... give the spray thing a whirl.... how does it change when revving the engine in neutral?

[billgatese30]

ok then

its constant hissing, possibly a vacuum as it is sucking air in possibly??

the note doesn't really change much when revving in neutral, only when under load, at some loads it dissapears and at other is seems to be louder. yet after long acceleration (i.e. upto 3-3.5K) then on the over run there is nothing.

i need to get hold of some carb cleaner, will easi-start do the same job??

gonna find the little bugger as its doing my tits in at the moment.

[Borderbmw]

try squirting wd40 onto the inlet manifold and it should briefly stop the hissing if its a leak,easy-start is quite flammable so i wouldnt advise it mate,just in case

[billgatese30]

ok hten......problem solved, well almost.

no 6 cylinder inlet port is sucking, the gasket has blown out slightly and i am getting and fitting it tomorrow.

[Adammcf]

What did I tell you?! lol

[billgatese30]

What did I tell you?! lol

got it fixed this afternoon, right bitch to get into some (make that most) of the nuts. but its done and is sweet.