So, from somewhere, I'm getting some decently stinky exhaust fumes out of my 307. There are a few known holes in the long pipe from the cat converter to the muffler, and I plan on getting a new one welded in this weekend. What I really want to know about are other spots that are prone to leak exhaust on these cars. Do the exhaust manifold gaskets give out after a while? Do the joints for any of the emissions controls specifically give way? Air pump screw up?

Also, is there any way to force the AC to stay on recirculate? Is there even a recirculate option on these cars or does it always draw outside air?

i've been told and have read that its not good to leave the ac on recirculate because it makes the blower motor work too hard i believe on the electronic climate control a/c you can't leave it on it will go back to drawing outside air after a while and on newer cars it also goes off after a few mins its usually only for when the car is extremely hot.

if the fumes are going in through the a/c then it all depends on when it happens do you smell the fumes when stopped or when driving at 30+?

It is very possible that one of the bolts could have just loosened so youcould check for tightness of the manifold and flange bolts then work your way back checking all the bolts to see that they are there and that they are tight.

Yeah, I figured it'd stress the blower motor a little, but I'm getting cancer damnit!

The stink only happens while stopped with the engine idling. Once the car is moving, no more stink seems to occur. Seems to only get into the car while the A/C is on. With the windows down, which is rare in Florida, the car is pleasant. You can smell the stink outside the car too.

Is it the sulfur smell? If so that is typically a cause of high sulphur gas in cahoots with a too rich fuel mixture.

Often only smelled at WOT (like when someone in front of you mashes the loud pedal), but if at idle, then look for plugged air filter, bad plugs, cap, rotor, etc. Anything to not complete the combustion process.

well smell the exhaust coming out of the muffler if thats exactly where the smell is coming from then you dont have a leak and your engine is just not properly maintained at the moment.


If the exhaust doesn't smell the same as the odor you get into your car then you may have an exhaust leak that is getting into your cabin.

It could also be that the a/c is putting more stress on the engine and it causes it to run bad etc. so the emissions are affected and you can smell it inside the car.

Nah, it's not that farty smell you get from sulphur, it's that smell of funky '87 octane gas burning. My '67 Camaro has the same smell, but only out of the tailpipes. There's absolutely zero emissions controls in the Camaro though, so I'd expect the exhaust to stink coming out of the back.

I know my car isn't running rich because it's still suffering from a mild fuel starvation knock. I plan on adjusting the rich-stop screw a little when I get home from work now that I finally found a diagram of which screw it is!

I had the car running while on jackstands the other day, and while crawling around underneath I couldn't get a whiff of the smell. I did get a good sound of where the exhaust was leaking from a few holes in that long pipe though, so I'll be plugging that up soon. If I sniff around under the hood, the major part of the stink and possibly a little exhaust leaking can be detected on the driver's side. Should I be chasing the exhaust manifold or that crazy joint where the emissions control thing diverts exhaust over the intake manifold? The EGR is tight and has a new gasket, so it's probably not that.

My A/C is definitely on its way out. The bearings are worn enough to produce a whistle, and to my knowledge, there is no way to deliver grease to them. I don't think the A/C is causing it to stink though, even though it should be putting a decent load on the engine. The A/C could explain my 12-14mpg vs. the advertised 17mpg :D