Under bonnet noises?

[Vee-ard]

Besides the injector ticking, I seem to have a somewhat loud air sucking noise that definitely isnt just standard intake for a V8. Seems to get louder with increased RPM.

Not a vacuum leak of some kind is it?

Tried to locate it, but because it isnt tapping, the old stethoscope tricks with screwdrivers and garden hoses doesnt really work. if I had to pick, it does sound like the passenger side though.

[jokerflingo]

Besides the injector ticking, I seem to have a somewhat loud air sucking noise that definitely isnt just standard intake for a V8. Seems to get louder with increased RPM.

Not a vacuum leak of some kind is it?

Tried to locate it, but because it isnt tapping, the old stethoscope tricks with screwdrivers and garden hoses doesnt really work. if I had to pick, it does sound like the passenger side though.

Not the air flow meter leaking is it? Although if i remember correctly they make quite a loud noise anyways.

[hako]

I'd also look at the exhaust headers as it could be exhaust gas leaking - this would increase and get louder with revs whilst a vacuum leak usually will decrease with revs.

[ephect]

if its intake, u can spary crc along the intake pipe, if theres a hole, it'll suck it in n the revs will increase as it takes in the crc.

[Vee-ard]

I'd also look at the exhaust headers as it could be exhaust gas leaking - this would increase and get louder with revs whilst a vacuum leak usually will decrease with revs.

I was actually thinking this, because occasionally I can smell exhaust fumes in the cabin briefly on a cold start. It normally disappears pretty quickly though. Is this normal or a sign that the headers are definitely leaking?

I have pacemakers, but they were put on by the previous owner, and judging by the botched half ass shit he did to the rest of the car, I wouldnt put it past him to have self installed the paceys and miss something important (like gaskets) out. How can I tell if I have a header leak? put the car in the dark and use a torch?

[hako]

The way I tell is either to listen closely whilst revving the engine a few hundred revs and/or run the hand as close as comfortable to the exhaust manifold gasket area whilst revving the engine as before. You can also use a length of garden hose (cut some from the neighbours - it works better) and run it along the header. You may need to do this from under the car as well.
If you can smell exhaust fumes on a cold start that points to a header leak.

[VS6]

usually you hear the motor under the bonnet .... jks man

[Vee-ard]

usually you hear the motor under the bonnet .... jks man

Hey thats pretty funny man, I can see you're gonna be around here for all of about 10 minutes before you get banned.

[VS6]

hahaha calm down

[DannyboyDS]

yeah ive burnt myself pretty bad using the old feel by hand method, i'm a bit of a twat though, just check not an abba fans sig.

erm, the dark and torch works quite well for me, thats how I have always done it.

[Chris E]

Not to sure about it being a leaking exhaust, the exhaust manifold wasn't tightened properly on my v6 and it made a ticking noise rather than a sucking noise

100% sure it isn't to do with the intake? tightened all the clamps etc?

[hako]

yeah ive burnt myself pretty bad using the old feel by hand method, i'm a bit of a twat though, just check not an abba fans sig.

erm, the dark and torch works quite well for me, thats how I have always done it.

How do you use a torch in dark looking for exhaust leaks? (and I'm not having a go at you!)
I'm always eager to learn new methods.

[Vee-ard]

I think the idea is that the smoke or fumes are more visible when shining a torch over the manifold in the dark.

Sort of how a laser illuminates an aerosol.

[ScoHar]

a header leak will sound alot like a ticking injector not a sucking noise, as said above best way to check for leaks is spray some CRC round the intake manifold gaskets, all the joins in the intake, although if its a 5.0L it's probably just the normal 5.0L noise, they are terrible for induction noise, especially if you've put a pod filter or opened the airbox or similar mod.

Another thing to check would be the vacuum lines going to the (unsure of terminology) Vacuum Ball under the passengers side guard near the front, that may have cracked or check the hose to.