Exhaust manifold leak cause other issues?

[undefined0000]

I have a leak at the exhaust manifold. I discovered it because there was a loud wooshing sound coming from the drivers side under boost and it just sounded like a cracked window, but I revved it in park and same sound. Was looking for vacuum leaks and found that a stud is completely gone. I won't be able to get the stud and gasket for a few weeks and I'm wondering if this will cause any serious mechanical issues?

 

[sstigijr]

No it shouldn't cause any serious issues. Just don't boost the car until you take care of it.

 

[dsmer1]

I have a leak at the exhaust manifold. I discovered it because there was a loud wooshing sound coming from the drivers side under boost and it just sounded like a cracked window, but I revved it in park and same sound. Was looking for vacuum leaks and found that a stud is completely gone. I won't be able to get the stud and gasket for a few weeks and I'm wondering if this will cause any serious mechanical issues?

yes exaust leaks cause a verity of problems. one, it will cause late spool up, it will cause an incorrect o2 sensor reading, which will make you car run lean depending on how bad the actual leak is. so, replace it as soon as you can. and it can also fry electrical parts. ive fried 3 alternaters that way

 

[XiKeiyaZI]

A Pre-02 sensor exhaust leak can cause issues in driavability depending on how bad it is. If it is a large leak, have fun driving it. If it's something small (as most of us deal with daily anyway) you won't really notice too much save for the possibility of the smell of fuel under boost and awkward AFR readings if you have a wideband.

You are essentially loosing vital fuel readings before they can reach the 02 sensor which is what helps the ECU determine how much fuel to add or pull from it's next signal. Without these readings, the ECU thinks there is less fuel and thus adds more, enriching the mixture as detailed in the post above.

Again - all depends on how severe the leak is.

 

[micha118833]

+1 I would say that if you have a leak before you get to the turbo then you aren't getting full boost either. any air escaping is air not helping the turbo spool up

 

[undefined0000]

Thanks for the input guys! Can anyone point me in the right direction in installing the stud? I heard of bent valves with exhaust manifold leaks and it scared me. The leak seems bad to me because at higher rpms, I hear a loud wooshing sound. It sounds like the turbo spooling, but scarier, and it comes from the driver side. I'll post a pic of what happened in a sec, on my iPhone.
There it is.

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[007jimmy]

Take off the exhaust manni and double nut the stud and thread it in. Dont torque it in, just snug.

Holy RTV man.

 

[undefined0000]

Will the exhaust mani come off alright with having the turbo there and all? Lol, and the RTV is from the previously s owner, I'm gonna undo it as soon as I can get a valve cover. My PVC hole thing is borked

 

[007jimmy]

Yup undo the 4 turbo bolts and take off the nuts for the exhaust manni. Might as well look into a new gasket for the manifold/head and the manifold/turbo.

 

[undefined0000]

Yup undo the 4 turbo bolts and take off the nuts for the exhaust manni. Might as well look into a new gasket for the manifold/head and the manifold/turbo.

one last question . Can I install the stud without removing the manifold? Depending on how much a stud and nut are, I might be able to use my spare change to grab a pair and slap it on till payday to lessen the leak

 

[007jimmy]

I have personally used a grade 8 bolt with the same thread pitch and a matching lock washer to get by. It worked fine for the time being. If you have exhaust soot blowing out where there is no stud it might not be able to get a clean seal so thats why i reccomended a new gasket. You could try to put the stud in but it would most likely be a PITA.

 

[dsmer1]

Yeah I would take the entire exsaust mani off because most likely the hot exaust gases fried the gasket near the bolt, plus it would suck installing the bolt and figuring out the leak is still there. Might as well do it right the first time.

 

[undefined0000]

Alright, so just to confirm. Just remove all of the mani-head bolts and the 4 bolts on top that attach to the turbo and it should slide right out? Will the turbo be still held up by anything? sorry about all the dumb questions, just never did exhaust work with a turbo there.

AND to confirm, a leak there would indeed generate a wooshing sound? Anything else it could be? It only starts making the sound after the car is warmed up. I can take it in the morning and I have to hit boost to get on the highway, it doesnt make the noise when I get on the highway, but after, it starts to make the sound.

 

[Jon91TSi]

one last question . Can I install the stud without removing the manifold? Depending on how much a stud and nut are, I might be able to use my spare change to grab a pair and slap it on till payday to lessen the leak

Doubtful. The motor mount/power steering bracket is in the way. There's no possible way to get a socket or open end wrench in there. What I did was use a 6" carbide bit on my rotary and took enough material off so I could get a socket on the nut. I'm using ARP's, but the concept is the same for the stockers. I tried everything possible, but in the end I had to grind off about 1/4". I blended it in and shot it with black paint, so you'd never know any modification was ever done.

I would just hope that the original stud isn't broken off in there. If that's the case you'll need an angle drill to get that sucker out, or do it when the head is off the car.

Alright, so just to confirm. Just remove all of the mani-head bolts and the 4 bolts on top that attach to the turbo and it should slide right out? Will the turbo be still held up by anything? sorry about all the dumb questions, just never did exhaust work with a turbo there.

AND to confirm, a leak there would indeed generate a wooshing sound? Anything else it could be? It only starts making the sound after the car is warmed up. I can take it in the morning and I have to hit boost to get on the highway, it doesnt make the noise when I get on the highway, but after, it starts to make the sound.

The turbo is supported by the downpipe and oil return, as well as the hardlines for the coolant and oil. Yes, pull everything off and the manifold will come right off. If anything of the studs/nuts feel like they are binding when you're taking them off, stop, apply heat with a torch (MAPP gas works great for this), and see if it will break free. If you spend the extra for a copper gasket you can re-use it over and over.

 

[Cdc1221]

Yes, your downpipe will hold the turbo up. I normally pull the turbo and mani as a unit and split them though. Great opportunity to check the turbo for shaftplay, oil leaks, cracks, etc.

 

[undefined0000]

Alright. Ill get this done as soon as I can get the pesky $12 so I can order the parts. I'm so poor recently.

 

[undefined0000]

can anyone explain why I only have the wooshing sound after the car is run for like 10 minutes? I thought exhaust leaks worked the other way around

 

[IrishBeatdown]

I recently swapped exhaust manifolds back to the stocker temporarily, and apparently last torque the exhaust mani hole PO tapped to m10, and the standard 2 studs next to it all spontaneously abandoned their thread at the same time. Tried to bolt up as best I could and fired it up. Sounded nothing like a whoosh, more like an open downpipe for me, but this leak was bad. Needless to say my AFR's were all the way up in the 18 range so massive exhaust leak haha. helicoils come in today. I didn't think the afr's were going to be that bad, glad i had a wideband because driving that lean would have been horrible. Based on that i would recommend not driving it, although im willing to bet my exhaust leak is light years worse than yours.

 

[undefined0000]

I recently swapped exhaust manifolds back to the stocker temporarily, and apparently last torque the exhaust mani hole PO tapped to m10, and the standard 2 studs next to it all spontaneously abandoned their thread at the same time. Tried to bolt up as best I could and fired it up. Sounded nothing like a whoosh, more like an open downpipe for me, but this leak was bad. Needless to say my AFR's were all the way up in the 18 range so massive exhaust leak haha. helicoils come in today. I didn't think the afr's were going to be that bad, glad i had a wideband because driving that lean would have been horrible. Based on that i would recommend not driving it, although im willing to bet my exhaust leak is light years worse than yours.

See, at idle, it sounds perfectly normal. AFter driving for about 10-15 mins when the exhaust mani warms up, when I get higher than like 2500rpms, theres a loud wooshing sound that occurs, only above that range.

 

[XiKeiyaZI]

See, at idle, it sounds perfectly normal. AFter driving for about 10-15 mins when the exhaust mani warms up, when I get higher than like 2500rpms, theres a loud wooshing sound that occurs, only above that range.

Best bet? Get us a video.

 

[undefined0000]

Best bet? Get us a video.

Alright, I'll try. Not sure if you'll be able to hear it over the engine noise and exhaust. Its just a massive air wooshing sound. I'm confident that its not the turbo because I can hear it when I pass buildings on the passenger side, then on the driver's side is the loud wooshing, but there aren't any vacuum lines over there other than cruise and FPR, and I tested them for leaks, none.

 

[undefined0000]

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Theres another picture of the same area, looks like exhaust crap is collecting and its hopefully what is causing the wooshing sound. Gaskets, new stud and nut and new manifold are all in the mail.

 

[XiKeiyaZI]

That's a rather important stud/nut/pressure point on the manifold. It certainly looks like it's seem some exposure to exhaust. Hopefully there isn't a stud already broken off beneath the manifold, otherwise you're going to have a hell of a day.

 

[Drewthebear]

Yeah Im having the same problem, although i only notice it when i seafoam it, Im looking into getting a performance one though.

 

[undefined0000]

I took the manifold off today, and cleaned up the gasket, put the new stud and nut on (The last stud literally fell out). The wooshing sound went away! Although, after a few 0-100 runs and hitting 15psi, I lost one of the nut in the same spot. Thank goodness I have a spare.