First of all, it's "header" (singular), not headers. If it's just a crack and exhaust is leaking, it won't damage the motor. However, you won't pass emissions and smog. You can either try to seal it with a high temperature exhaust sealant, take it to your local muffler shop where they can weld it shut, or buy and install a new OEM header. I actually happen to be selling my stock one.

btw, it shouldn't be smoking at all. An exhaust leak you can hear, but never see. Are you burning oil? You should bring it by a shop and have them take a look at it. It could be a blown gasket as well.

 

You can either try to seal it with a high temperature exhaust sealant, take it to your local muffler shop where they can weld it shut.

I had a crack on my 95 Prizm exhaust manifold, and i tried JB Welding it. LOLz, that lasted about 20 minutes, then it vaporized. So whatever you use, it'll have to be higher temp than that. Welding it is probably the most cost effective option.

But it could also be a ruptured exhaust gasket.

 

alright, but how do I get to the part that is leaking to seal it? I can't see the crack right now, just the gray exhaust smoke that come out. And its not too bad, you can only see the smoke when the hood is up, it isnt noticable when the hood is closed during normal driving. But I want to know how I can get to the crack?

 

just the gray exhaust smoke that come out.

Somethin ain't Kosher...

as Rollatuner said, you shouldn't be able to see the exhaust. You need to determine which kind of smoke you have and what color it is.

Blueish smoke = oil
White smoke = coolant
Black smoke = fuel (running absurdly rich)

 

Mine leaks exhaust where the manifold attaches to the downpipe. There is a donut gasket in there that keeps getting torn up. Mine is being caused by the motor mounts allowing too much movement. As everyone has said, can't see it, but I can hear it. Especially under load.

 

I had the same problem after my aftermarket header. Replacing the donut gasket is one big crap shoot. You might fix it 50% of the time. I just brought it to my local muffler shop and had them weld the two sections together. No leaks now.

 

Your motor mounts could have been on their way out, and the clutch replacement could have damaged them. Or they could have botched the replacement, that is also 100% possible.

Only place I could think of coolant leaking would be from the head gasket (not likely if engine is running well otherwise) or a heater core hose. Unless there is a freeze plug above the exhaust manifold.

I'd start with the shop that replaced your clutch with a great big "hey, WTF meng!"

 

Yea I dont know, I didn't notice any engine movement whatsoever until after the clutch was done. I want to take off the heat guard to see if I can find a crack anywhere, but 4 of the bolts holding it on are completely rusted, I wont be able to get them off at all, and even if I could, its not gonna go back on. Its a 99 CE with over 200,000, the bolts are really old. And since the clutch replacement, my check engine light has also come on. At autozone they did a diagnosis, it came up as a burnt out o2 sensor, the first one before the catback, would that tie into all of this at all or is that a completely seperate matter?

 

Before people make wild guesses with their guts about things.
Regular exhaust can look whitish/gray, if you're burning coolant, it will bellow out of the exhaust pipe and smell sweet.
As for manifold cracking, yeah its a common issue with cast iron manifolds, you cant seal it with anything, the temperatures are so high that it will just burn off. Also the crack will grow as the manifold expands and contracts due to temp (another reason why any sealant wont stay on long). Only way to stop it is drilling holes to the ends of the crack to contain it and then have it tigged or stick welded with a cast iron stick/filler. Migging, etc will only be a temporary repair.

As for it being dangerous to the engine, well it is. If the leak is before the O2 sensor, you're not giving the correct signal to the ECU and fuel delivery will be altered. If it reads rich, it will lean the fuel mixture, and vice versa. So the burnt O2 sensor can tie into this very well indeed. Lean mixtures increase EGT's as does a rich mixture, however a rich mixture can in some cases heat up the manifold and O2 sensor. Also a rich mixture will bring in alot of soot that will clog up the O2 sensor.

they might have messed up a mount putting it back in, now my motor is unstable and also allows too much movement, which probably ended up causing a gasket to break.

Mounts wear out, doubt they took the engine out to replace the clutch, mostly they just drop the transmission. As for gaskets breaking, naah, the exhaust manifold is tight with bolts and cant move and the flex mount will enable movement.

If you believe the leak is directly on top of the manifold where you can see it, you can spray soapy water on it and turn the motor on. Bubbles will form.

Yep, because the water will quicky boil if theres a hot manifold.

if you believe the leak is on the bottom, reach down there and actually feel the texture of the manifold. Do this when the engine is cold.

Hahaha, I'd like to see someone do this with a hot manifold :lol:

 

Regular exhaust can look whitish/gray

Yeah, that's water vapor, and I've only seen it at the end of the exhaust, after it begins to cool and condense. Never seen it out an exhaust manifold or downpipe.

When my 95 cracked, it was right in front of my face. I could only tell by the sound, never saw any vapor. However, I seriously doubt he's burning coolant.

 

A leak in the exhaust will definately squew you O2 sensor readings. You won't be able to see it but for every puff of exhaust that comes out a small bit of air gets sucked back in. This will cause a false lean reading on your O2 sensor. Your PCM will try to richen the mixture, which could account for the off colored exhaust you claim to see. See what you can do about the motor mount issue's first, if it is your manifold to extension pipe donut, it will likely just wear out prematurely if you repair it and the engine is still moving excessively.
Don't worry about the CEL untill after the exhaust leak is remedied. Fix the mounts then the leak, disconnect the battery and reset everything and hope for the best.
Good luck

 

Exhaust leak damages Catalytic Converters

A leak in the exhaust will definately squew you O2 sensor readings. You won't be able to see it but for every puff of exhaust that comes out a small bit of air gets sucked back in. This will cause a false lean reading on your O2 sensor. Your PCM will try to richen the mixture, which could account for the off colored exhaust you claim to see. ...

Then extra rich fuel will burn hot in the exhaust and melt out the some of your catalytic converter. Debris from the catalytic converter can plug your exhaust and cause back pressure, which also makes the engine run poorly. But worse is that your damaged catalytic converter(s) can be expensive to replace (up to $1,500), and your car may fail the State emissions test until the catalytic converts are replaced.
An exhaust leak can damage your O2 sensors, because exhaust leaks let in cool air. The O2 sensor needs to run at about 600 degrees, or their life is shortened. It may cost about $500 to replace one of the O2 sensors.
Speaking from experience, a little exhaust leak can cause big damage to modern cars.

 

yea it doesn't smell sweet like they said coolant would, its just really light colored smoke coming out. No unusually sounds though, I don't know. And the people at autozone told me the light is on because a wire in the o2 sensor is burnt out, they did a diagnosis on it. The check engine light would probably be on anyway though because of the leak altering the o2 sensor readings.

 

Just take a good look at the manifold once you get the heat shroud off, you will be looking for soot or carbon tracing around the crack. If the heads of the bolts are really bad, I have cut slots in bolt heads before and used an impact screw driver to break them loose, or sometimes a 3/8 socket fits better on a rusted 10mm head bolt.
Good luck

 

I brought it to a shop today, they're gonna look at it later and call me about it and give me a price estimate and what the problems are.

 

I hope its the same shop that did your clutch, from the description it sounds like they could be partially responsible. Or would have been nice if they at least alerted you to the issue

 

Yea its the same shop, if they don't bring it up first then I'll have to refresh their memory about the clutch work they did at mysteriously exactly the same time my engine started shaking and became unstable. Maybe their do the engine mounts and exhaust manifold for free, not sure. But they always have a nack for finding the part that will cost me the most. If it turns out they want 200 for a new exhaust manifold, i'm gonna go on ebay, get an aftermarket header for around 100 and just put that in with a friend I know that used to own a shop.

 

You want to know if youre mounts are bad? Put the car in gear, STAND on the brake, and rev the engine. Again, I emphasize, STAND on the brake, otherwise you'll take off. When I give it gas like that, Somebody might as well yell Gentlemen start your engines, cause it sounds like I'm firing up in the pits at Daytona. The torque on the manifold opens my exhaust leak wide open and she roars.

 

Its a 5 speed, I'd need 3 feet lol, but yea the engine mounts are bad. The mechanic called me back, I need 2 engine mounts (roughly 100 each he said) 2 new o2 sensors (189 each) the exhaust manifold is fine but a donut seal or something is broken (15 dollars) and because my o2 sensors weren't reading properly, I have a carbon buildup in my catalytic converter. In this last month alone I've spent over $1000 strictly in repairs, nothing else. Now here's another $600+ in more repairs. To say I'm pissed would be an understatement.

 

The rest of those prices look about right, but thats too much for the O2 sensors. Ask him how much for labor if you bring your own parts, and check out the prices on rockauto.com Sometimes you can get some better prices that way.

 

As I said in a previous post, don't worry about the O2 sensors untill after the exhaust and engine mount issues have been resolved. I would be surprised if they don't start reading correctly after the exhaust leaks have been fixed.
And it looks like you need to find a new mechanic, your present one must have too much overhead or too many ex-wive$ to treat his customers right.
Lowtech.

 

$500 for an 02 sensor? damn.

i paid about 100 for mine.

 

I would hope that price is installed.

 

I had a similar problem with an exhaust leak and it ended up being the 'donut gasket' that mates the header to the exhaust pipe. Cost me $100 bucks to get it fixed....