Possible air-leak on my 16v inlet....

23rd December 2008, 22:11

Serviced the car the other day. It had the works. Whilst myself and my mechanic friend were warming the car up and flushing through some new coolant he noticed a very subtle high-pitched squeal coming from the inlet side. He put some weight on the entire throttle body/inlet assembly to see if it was tight and the car just cut out. If there is indeed a slight air leak then the further separation of the inlet manifold from the block is surely going to make it stall......right?

I'm planning on tackling the H/G for good measure when I'm back up north and (correct me if I'm wrong) with the head gasket set I've seen on eBay it comes with a new inlet manifold gasket. If I fit that and tighten it all up (which might be all it needs) then hopefully this should sort it.

The car has had everything replaced recently with the exception of H/G and cam belt. Cam belt has been looked at and seems too have plenty of life so I'm not worried about that, but I am keen too change the H/G for good measure so I know it's running as sweet as poss.

Any other ideas on with this 'high pitched' noise could be then let me know

Cheers.

24th December 2008, 01:28

Dont quote me on this depending on where the leak is it can cause stalling but usually an air leak on the inlet side would cause your rpm to increase. Have you checked all your sensors that bolt into the manifold and your vacum pipes for holes?

24th December 2008, 02:36

yea if it was leaking air after the throttle body the idle would be all over the place. but, if you're doing the HG anyway it'll give you a chance to check it. i'd be suprised if the manifolds come loose, normally the studs are pretty tight.

24th December 2008, 07:17

I find the best way to check for an air leak is a can of wd40. Spray across joint. rpm will pick up when you find the part that is leaking. If you are going tochange the hg then for the sake of £12 for a new belt is nothing. I would anyway as a matter of course.

24th December 2008, 08:02

Quote:

Originally Posted by R555GED

Dont quote me on this depending on where the leak is it can cause stalling but usually an air leak on the inlet side would cause your rpm to increase. Have you checked all your sensors that bolt into the manifold and your vacum pipes for holes?

I'll quote you!

That's exactly right. Even the smallest of air leaks will cause the revs to shoot up, as it's just like opening the butterfly.

24th December 2008, 09:53

Quote:

Originally Posted by adamsax

Serviced the car the other day. It had the works. Whilst myself and my mechanic friend were warming the car up and flushing through some new coolant he noticed a very subtle high-pitched squeal coming from the inlet side. He put some weight on the entire throttle body/inlet assembly to see if it was tight and the car just cut out. If there is indeed a slight air leak then the further separation of the inlet manifold from the block is surely going to make it stall......right?

I'm planning on tackling the H/G for good measure when I'm back up north and (correct me if I'm wrong) with the head gasket set I've seen on eBay it comes with a new inlet manifold gasket. If I fit that and tighten it all up (which might be all it needs) then hopefully this should sort it.

The car has had everything replaced recently with the exception of H/G and cam belt. Cam belt has been looked at and seems too have plenty of life so I'm not worried about that, but I am keen too change the H/G for good measure so I know it's running as sweet as poss.

Any other ideas on with this 'high pitched' noise could be then let me know

Cheers.

not had that noise, but it is common for the inlet manifold nuts to come loose over time, if there loose take them out and thread lock them and put them back in.

I used to have cruise control because of it.

24th December 2008, 10:10

Sounds like the ICV air tract is blocked, or the ICV is nackered and almost shut. Then the pressure is cutting off its air supply. (The bit seperate at the top of the TB is where the ICV pulls in its air)

But dont forget if theres air leak to the inlet, then the MAP sensor will be getting wrong readings and sending the idle crazy too.

Id pull all your sensors off, give them a good clean, check all there seals then start again.

24th December 2008, 12:17

Cheers guys.

My idle is fine so that would rule out an out-and-out leak.

I reckon I'll take the inlet off, give it all a good clean and a fresh gasket. Scrub up all the sensors and take it from there.

Ta muchly boyo's

24th December 2008, 12:23

Quote:

Originally Posted by Ste

Id pull all your sensors off, give them a good clean, check all there seals then start again.

Do you no were all of the sensors are located ??

So i could check mine

24th December 2008, 12:30

i agree, might aswell change belt and then its done, if your h/g goes its not the end of the world, if a dodgey belt goes it can cause alot more seroius problems, beside your guna have to remove belt to do h/g

24th December 2008, 12:37

Quote:

Originally Posted by John_1.1i

Do you no were all of the sensors are located ??

So i could check mine

yes. there right in front of you around the engine. Jesus john.
You dont even have 16v.

24th December 2008, 12:39

Quote:

Originally Posted by Steve_VTS

yes. there right in front of you around the engine. Jesus john.
You dont even have 16v.

calm down lol, no need to be agressive

I wasnt on about a 16v, i was on about a 1.1i

Sorry for winding you up

24th December 2008, 13:11

Quote:

Originally Posted by John_1.1i

calm down lol, no need to be agressive

I wasnt on about a 16v, i was on about a 1.1i

Sorry for winding you up

nothing agressive about it lol

24th December 2008, 18:26

Did all I said.

Put some STP injection cleaner through for good measure too.

Its also highly likely im being a tart and worrying about nothing.

LOL.

24th December 2008, 18:37

have you checked the vacum pipe that is near the map sensor? mine makes the same noise if i pull it out