Exhaust Manifold Leak

Hi Group: Hope someone here can help me with this question.
I've got a minor leak in my exhaust manifold of my 2000 civic. I'm wondering whether I'm doing my motor any harm by not having it repaired right away. It
doesn't seem to be affecting performance in any way, but I've been told by a mechanic that it's there and I think I can hear it.
I'm also curious about the cost of repairing it. I'm in the Toronto area of Canada.
tia
Peter H
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Peter H wrote:

The potential for damage depends on where the leak is located. If the leak is at the junction of the manifold to the head, then the leak should be fixed promptly. Exhaust leaks at the manifold gasket have the potential to damage the flange sealing surface on the aluminum cylinder head. I witnessed this on a car owned by someone I know. He drove around with a very distinct sounding exhaust leak for several months. By the time he got around to replacing the manifold gasket the head had already been damaged and a new gasket made no improvement. If, however, the leak is from the exhaust manifold itself, then driving around with it for a little while might not be too offensive. It would be best to closely evaluate where exactly the leak is coming from and proceed appropriately.
Eric
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My favorite way of finding an exhaust leak is with a shop vac. Put the hose on the outlet side, run the vac a minute to get any extra grit out of it, and duct tape the hose to the exhaust pipe. It lets you work on a cool engine and produces an amazingly strong jet from even a small leak. You can easily feel it with your fingers.
Don't forget to remove the lash-up before driving! 8^P
Mike
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It should be a cheap fix if it's just the exhaust manifold gasket.
Exhaust manifold gaskets run around $20Cdn ish for a Cdn Tire brand. I would assume the dealer be around $25+. Which Civic do you have DX, Si, SiR?
Chris

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chris wrote:

Less than that, http://www.hondaautomotiveparts.com shows that the dealer list is around $12.50 US. Of course, the gasket for Canadian Hondas might be different.
Eric
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Eric wrote:

The only difference would be in price. :-)
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The leak may be from a crack in the exhaust manifold. This generation of civic has a chronic problem of having the cast iron manifold crack right in the middle in between the 4 cylinder exhaust pipes. When you turn on the heat in the car you will likely experience exhaust fumes being vented into the car if this is the case.
If you take off the manifold heat shield you will likely be able to see if you have a hairline crack.
Although the problem is relatively small, the repair costs are normally around $1500 CAD. This includes a new exhaust manifold (around $900), 2 oxygen sensors a few gaskets and labour.
If you're lucky and can find a shop that has precision welding equipment, and is willing to seal the crack, then you're looking at approx $350-$500 for repairs. Just be careful not to damage the existing O2 sensors because they are probably seized.
Peter H wrote:

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