Since Last Week I Keep Hearing A Clicking Sound From The Engine Bay When I Step On The Gas. I Asked Someone Who Is A Mechanic And At First He Said It Could Be The Exhaust Header Or A Bad Spark Connection, But After A Search Through The Engine He Is 100% Sure It's The Header Because There Is A Crack On The Header Where The Bolt Is Located. I Have Never Heard A Clicking Sound Coming Out Of A Crack Header Before. Could It Be The Exhaust Header?

On 73 240z If I Want To Take The Exhaust Header Off, Do I Have To Take The Intake Manifold And The Carbs Off First? I Have Never Done This Before, What Do I Need To Know In Advance For Nothing Having Too Many Problems At The End For Removing All Of These Parts? Thanks Again

an exhaust leak will make a sort of "clicking" sound.

you don't HAVE to take off the intake manifold, but it's a heck of a lot easier to take it off.

besides a new header/exhaust manifold, you will need a gasket.

Is that clicking sound you hear when there's an exhaust leak the sound of the intake valves slapping closed or something else?

First off, is it an exhaust manifold or a tube header ? You said it's leaking around the bolt hole, which one ? You have the bolts that mount to the head and the bolts down at the collector that the exhaust pipe mounts to. A manifold is going to be cast iron, a header is going to be steel tubes.

When the exhaust manifold/header is replaced, you will need to replace the gasket too. The intake manifold and exhaust manifold/header share the same manifold gasket. So the intake manifold will need to come off as well.

I agree about the intake coming off, but tell us, does the sound diminish once the engine is warmed up?

first i thought the crack is on one of the exhaust header bolt but i guess i am wrong there are more than one crack now. please look at the picture. the cracks are on each tube of each header pipe. i dont know why there are small tubes on each header pipe.

the sound doesn't diminish after the engine is warming up, it actually gets worser after the engine warms up.

i found a header (MSA 3 into 2 Headers)from motorsport online store, does any one know do i need the one with smog or without smog and do these headers come with a gasket, if they don't, how or where can i find a good header gasket? thank you all again.

MSA sells a good header. Saul of MSA was at one of our Z club meeting and he told us the way he installs the header that they sell without it it leaking. I did not take notes on what he said so you are going to have to call him and ask. He will talk to you for sure. I recently installed one of the older MSA headers which were real prone to leaks, I used a medal gasket and cooper RTV, it started to leak a week later, so I re tighted the header bolts and it seems fine again. The newer MSA headers are supposed to be less prone to leaks, they improved the flange some. I went with the older MSA header because it was free.

on my 73 240z E88, if i want to get the MSA 3 to 2 headers, do i need the one with smog or without smog? thanks again

73 is smog exempt. you do not need the smog holes (it looks like yours were filled anyway)

there have been clearance issues with the 3-2 header and SU intake manifold in the past. not sure if it's fixed, but just something to watch out for

I just installed a MSA 3 into 2 header on my 73. I changed intakes to a 72 w/roundtops. No clearance issues.

Quick ? If the header is leaking loud enough that u can hear it, Wouldn,t it backfire when u let off of the throttle? :stupid: