Hi..I have a 99 civic lx and I was looking underneath today and I saw this leak on the picture.. Can someone tell me what gasket is between the area marked in red in picture? I wiped the leak a little bit but you can still see it..

http://img2.freeimagehosting.n...b.jpg
http://img2.freeimagehosting.n...e.jpg

 

looks like your rear main seal

 

Can you be more specific man? what do you mean by rear main seal? Is it the seal between the tranny and engine?? Is it engine oil that would be leaking or tranny oil???

 

rear main seals the block where flywheel meets the crank. You'll be leaking engine oil. If it leaks and its black, whether it smells or not, it should be motor oil.

 

How much does it cost to replace it....parts+labour at the mechanic?

 

most regular shops would charge like 250-300. since they have to drop your tranny. i just had my clutch done and changed my seal too it only cost me 170 though. if you have mechanical know how you could do it yourself, just have a manual. i would have did mines but my complex frowns on that working on your car in the parking lot thing. just look around.

 

Is it harmful if I just left it as is? Would the leak get worse??

 

If left alone it could get worse. If this happens it gets on the clutch and makes the clutch slip and well you are losing oil.

 

looks like your oil pan, do you have a nothe pic from an diffrent angle?