[dillon134]

So, I've had an exhaust leak for a while now and suspect the Y-Pipe but have looked and don't see the telltale signs of black soot residue anywhere. Today, I climbed underneath to try and get a better look and took this picture.

This looks an awful lot like a cracked weld to me but wanted to get another opinion. Assuming that is a crack, I wonder why the immediate surface area isn't black as can be.

Thanks.

 

[TKOPerformance]

The Y-pipe is constructed such that the flex joint is not simply installed between two pieces of pipe. Rather, the pipe extends through the flex joint such that when they crack the exhaust gas has to make 270 degrees worth of turns to get out, which it won't do when the flow is moving with any kind of velocity.

 

[dillon134]

Thanks. So, I might have two exhaust issues then. 1) I can smell exhaust in the cab at idle and not moving, which, based on your comment, might indicate a Y-Pipe leak. 2) I hear a very loud swish sound coming from below the engine drivers side when accelerating/boosting. Boost never gets above 21. I'm thinking that I have an exhaust manifold leak on the drivers side. It is so hard to find because it only leaks while moving and boosting. Cannot recreate the swish/leaking sound rev'ing up while stopped. A purchase a borescope w/ 15 foot cable to hopefully see what's happening under truck while moving. Problem is that the camera is only good for close-up inspection. Can't see anything with it from a distance.

I may have to take it to the shop so they can find the leak for me but I hate to pay a guy to do anything on my trucks.

 

[TKOPerformance]

I would start with the Y-pipe problem and see if the other problem goes away. You may want to check and make sure all your manifold bolts are there and tight on the side you suspect too.