Greg Jansen

Hi

I've got a 2006 Cayenne with the 3.2 liter V6.

The car sounds like there is an exhaust leak. Pretty loud, seems to quiet down a bit after warming up. I was not able to find the leak visually, because it's a bit crowded in the engine bay. I decided to just replace the exhaust manifold and catalytic converter gaskets, thinking that must be the culprit. I removed the intake manifold, vacuum lines, and other parts to allow access to the exhaust manifolds.

When I took the exhaust manifold and converters off, the gaskets looked just fine. I though for sure I would find a broken gasket.

So where is the noise coming from??????

I also noticed in top rear of the engine, a bunch of cracks on it. What is this piece? Could there be an exhaust leak in it? Fluids seem fine, car seems to run o.k.

I'm at a loss as to where the exhaust noise is coming from. Any help or suggestions where to look would be great. It's definitely somewhere in the engine bay. Thanks!

Petza914

Those might just be casting lines and not cracks. See if they look any different when cold vs when hot as things expand or contract. For another rleak possibility, check the exhaust flex pipes underneath that allow the engine to twist a little independent of the hard pipes that run to the rear exit, providing the v6 has flex pipe sections (I'm more familiar with the v8 setups).

Greg Jansen

I didn't even know there was a flex pipe in there. I've been reading that it is common for the flex pipes to develop a leak.

I'm going to have to put everything back together, then check the flex pipes for a leak. There are two on the 3.2L engine. Two exhaust manifolds go to two cats, one of which has a flex pipe. The two cats join and there is another flex pipe after the Y.

Luckily, the whole assembly of two cats, the Y pipe and the flex pipes is only $225. That was a relief to find out. Now the only hard part will be taking the Y pipe apart where it meets the rest of the exhaust downstream. It connects low in the engine bay, right before it stick out from the bottom of the car. Not much room to work. I'll order the part and bring it to some local indy shop that has a lift.

dschu

I would just buy a small smoke leak detector online. I got one for $120 on Amazon (Autoline Pro) and it has saved me several times. The smoke smells kind of bad though. You can borrow mine if you're in NC.