Retserof

I often notice a strong exhaust smell in the cabin when I slow down quickly after moderate to hard acceleration. I can't see any damage to the exhaust system and it sounds tight.

Could it be due to rich exhaust leaking out the manifold and being drawn under the hood into the cabin air intake? I know some of the C5s had leaky manifolds. Or is it just rich fumes from the tail pipes being backwashed around outside the car to the cabin air intake?

MTPZ06

Pretty normal condition. It gets much worse if you delete the cats like some folks with LT's will do.

Mr.Bill

I have never noticed it ever in my car.

rws.1

You could be experiencing signs of failing catalytic converters.
The furfurol smell is quite pronounced when the cats aren't working properly

Bill Curlee

A new C5 Corvette never has OR should never have an exhaust smell in the cabin! If you smell exhaust,,you have an issue. Sure,,,,If you have the window open and the wind is at your back, you may smell some. If you smell it when the windows are closed, that is not good.

There are a few places where exhaust fumes can leak from the engine under the hood:

A.I.R. Manifold Flanges or piping
Manifold to Mid Pipe flange
Manifold to engine joint

Theres a cabin pressure equalization vent in the rear of your cabin. It behind the carpet on the drivers side right above the small storrage compartment. Make sure that it seals properly and is not damaged.

I thought my header exhaust system was gas tight. I seafoamed the engine and when I cranked it up, I found out that I had a significant leak at the A.I.R. flange on the passengers side. The small gasket between the flange was damaged and a small piece blew out. Lots of smoke came out that joint. A new gasket fixed that Right up.

BC

jrose7004

I never smell exhaust in the cabin of my car.

Carcass

Never.

Retserof

BC, thanks for the suggestions. I visually inspected the system some time ago and used a length of garden hose to listen for leaks at each gasket and flange weld, but all I found were pinhole gaps in the factory welds around the flanges at the rear ends of the midpipes. I wouldn't expect them to allow much gas to leak out or to be the source of the smell back in the cabin. I have Corsa mufflers, so there shouldn't be much back pressure after the cats.

I'll have to take a closer look now at the AIR system, bracket welds and the equalization vent.

Pete

MTPZ06

Guess I should have qualified my statement by saying "with the windows down". Windows up, no.

Bill Curlee

I agree. If you remove the CATs the raw exhaust smell will permeate your clothes if you stand behind the car. Its surprising how annoying that smell is. My wife KNOWS the second I walk into the house when Ive been around a catless car. I'm a motor head from WAY BACK when cars didn't have cats. I guess were all use to a better smelling exhaust.

BC