[WKvernich]

Hey guys I've been dealing with what seems to be an exhaust leak for the last month or so now. I'm 90% sure it's coming from the exhaust manifold area but I can't really figure out if it's a gasket or the actual manifold itself. When I rev the car while it's idling it can't really be heard but if you get it up to about 3k rpms while driving it's pretty loud. I know it's not lifters ticking because I've seen exhaust coming from that area on a cold morning. Any ideas?

[justAbullitt]

If you don't have a smoke machine, theres really nothing you can do other than remove the suspected manifold and inspect.

Sent from my phone

[WKvernich]

How hard is it to remove the manifold. I know it's in a pretty tight spot

[shanerob34]

all depends on what your idea of hard is, i mean i am a truck mechanic so tight spots aren't really a thing anymore. get yourself a ratcheting wrench if you don't have one, it will make it a lot easier. They're not that bad. are you outside the car when someone is raising the rpm or are you inside doing it yourself and listening

[WKvernich]

I revved it at the throttle body and inside the car it's hardly noticeable under 3k rpms. But past that point you can really hear it.

[shanerob34]

Did you stick your hand around in there I mean only so much can be determined with sound. Air is funny when it is leaking it can make it sound like it is coming from a totally different area. Stick your hand around if its a good enough leak that you can hear, then you should definately be able to feel it. Remember exhaust parts can get slightly warm lol.

[shanerob34]

on a side note, you might as well just throw headers on it, and replace the gasket while you do it.

[WKvernich]

Yes I tried feeling for it but didn't really feel much. Could it be where the header attaches to the rest of the exhaust?

[shanerob34]

it could be I mean without being there and hearing it, or seeing some pictures that could possibly do it justice I mean its kind of like a guessing game. Make sure all the studs are tight enough on the manifold. a gasket could be the culprit but its pretty much a guessing game for anyone to diagnose it properly, keep working you'll find it. And if you feel that it is the gasket area after you have worked hard trying to find it, just get a new one and replace it, most likely if it is the problem once you get the old one off you will know but then you have to get a new one anyways.

[WKvernich]

Yeah that's probably what I'll end up doing. I have a friend who is gonna cut off my catalytic converters soon so I guess we can go ahead and fix the exhaust leak while we're at it.

[shanerob34]

yea i mean exhaust leaks can be a pain. when you do exhaust work make sure to use the right clamps, youll get leaks if you don't
good luck bro hope you get it dont give up

[WKvernich]

Yeah it's a never ending battle lol. The car is gonna sound so good when I'm done though haha. I tons of visual parts I need to put on.

[95mustangGT/SVT]

Good luck man. Exhaust leaks usually are not hard to trace. Hold a rag or something over the echaust tip and it should get a lot louder if it's the exhaust.

[shanerob34]

+1 or stick a potatoe in it lol

[WKvernich]

Originally Posted by 95mustangGT/SVT Good luck man. Exhaust leaks usually are not hard to trace. Hold a rag or something over the echaust tip and it should get a lot louder if it's the exhaust.

Thanks I'll try that tomorrow. And I have noticed a little bit of black build up around the area of the suspected leak so that might be a good indicator.

[jeep45238]

Driver's side?

[WKvernich]

Originally Posted by jeep45238 Driver's side?

Yes

[jeep45238]

It's leaking from the dome flange. Crawl under there, remove the nuts, apply antiseize on the stud threads, and if possible buy two new nuts.

Tighten them up slowly and evenly. If you turn one half a turn, turn the other half a turn. Do this with a 1/2" drive and a breaker bar.

Once you get them tight, fire it up, and hop under the car and feel around the flange for leaks with your hand - you'll feel a slight puff of air hitting your hand.

If you do, turn it off, and give it another 1/2 turn to each until it stops leaking. You literally have to crush the steel of the mid pipe with the flange onto the dome evenly to create that seal.

Some people will apply copper high temp RTV to the midpipe-manifold joint upon install to help prevent this - others will put in a doughnut gasket.

I prefer to do it the OEM way - crush the steel evenly over the dome.



This is very common for people who just replaced a midpipe to have a leak at that location.

[WKvernich]

Thanks I'll try that out tomorrow. I know the car has a BBK o/r X pipe so that could be the likely cause.

[jeep45238]

Just be patient and alternate between firing up the car and feeling for leaks, and slowly turning the nuts. You probably won't get the leverage you need with a 3/8" drive.

Once you stop the leak, stop torquing, no more is necessary. This is a situation where a little extra is not a good thing, as it is possible to snap off those studs. That is why antisieze is very important, yet often neglected, for this install.