While doing my oil change yesterday , I noticed that my exhaust leaks water right at the connection from what looks like a y pipe to a metal mesh pipe ( which leads to rear of car ) . Here is a pic of the spot.

Could that be giving me a p0420 code in any way ( I know -- wishful thinking I'm sure )

Front of car is on the right side of pic.

 

myexcursion, I guess the questions that I would be asking are 2 fold?

1) does it only leak for a moment and then stop once the car gets up in temp?

2) if you turn off the A/C in the car, does the water leaking stop?

As for question 1, there is a certain amount of water that will build up in the exhaust since when you burn gasoline/petrol, one of the by-products is water (along with CO2 and some other minute items). So, when you turn off the car, the exhaust that doesn't leave the exhaust pipes will condense and you can get a small amount of water to build up in the exhaust system, which will lead to what you are seeing. But, as you can imagine, once the exhaust system gets back up in temp, this water will convert back to steam (or not condense in the exhaust to begin with) and therefore the water dripping will stop.

As for question 2, the A/C drain is right above the exhaust and while it may appear that the water is coming from the exhaust pipe, it is actually dripping down on to the pipe and then rolling around the pipe, making it appear to come out the bottom of the pipe like it was coming from inside the pipe.

 

Agreed with Thermo, water in exhaust is normal. Catalytic converter turns HC, CO and NOx into CO2, N2 and H2O so if your cats are brand new you will have alot more water in your exhaust compared if your cats have failed.