I'm having problems keeping the exhaust out of the inside of my 68 Convt'. No matter what I do, short of putting the top down, I can't keep the smell out. I am planning on re-sealing all of the vents, engine firewall gaskets, and ensuring I don't have any pin hole leaks in the body, which I don't believe I do. Anyone have this problem, is it something I'm overlooking, or am I on the right track.

Thanks,
Chris

First, I would look for the source. I would check for a leak in the exhaust system under the car.

i second jim answer but i find myself asking if you've run the exhaust out the back or have it dumper before the tires or under the car. check for leaks first and make sure your vents are closed!

Exhaust is dumped out at the rear of the car. Tail pipes stick out below rear valance. I believe I have a small leak at the exhaust manifold and Y-pipe on the passenger side. I did not think this would cause such an influx of exhaust. I'm still working the bugs out of the car after the restoration, and I'm finally getting to this one.

IMO if your exhaust system had NO leaks, even if your floor had holes you should not smell exhaust fumes as they are dumping out the back which would be past the holes in your floor. I am just using that as an example to make a point, not saying your floor is full of holes. LOL

Go fast! Really fast dont let it ketchup

i had the same problem in my 69 ta.when i ran the tail pipes where they came out originally it solved my problem.when they went out the back ;i got fumigated

The problem is the exhaust system, not possible holes as 68fb400 mentions. Just because they dump out the back doesn't mean that the ehxaust clears the chassis. There is a "backwash" turbulence behind the car, and it's a safe bet that the exit of the pipes are located in this area. (Most rear exit exhausts, imo, I have seen are defective. If the engine is running clean enough, you won't smell fumes.)

Effective systems are tucked tightly under the valance and downturned to ensure full exit of spent gas, and I would refuse any other designed system, meaning that most of the current systems, including the pos pypes, wouldn't meet my specifcations.

I had this problem in my '86 Caprice. I searched all over for rust and rot or leaks in the body. It turned out a tiny hole in the muffler that was dealer-installed caused the problem. It was a fabrication mistake that punctured the end of the muffler. I swapped in a new muffler and the problem was solved. Today, I would have just welded the hole shut, but at the time, I didn't have the gear. I think the news is that minor leaks in the exhaust are major inconvenience to the driver.

The dealer who installed the muffler installed Walker stuff. I tried to put in a claim for the new part with Walker under their "lifetime warrantee". They never returned any correspondance. I had to beat them up just to get the rebate paid.

That's the problem, I had the same, but on the drivers side, I was blaming all the trucks on the road but had a maifold leak. Once fixed your air quality will improve!

Are the pipes welded or clamped?

Check the obvious...manifold gaskets and flanges after that.

Unless you have a stout tailwind do I agree with backwash or turbulence...unless the entire exhaust system is degraded or the pipes dump out under the body somewhere.

Thanks fellas, I'm going to check and fix all leaks, if that doesn't work, I'm going to get some pipe extentions for the rear and temporarily run them beyond the valance with a down turn to see if that fixes it. I'll let you know what I find.

Thanks,
Chris

I had the same terrible smell problem last year after messing with the rear chrome divider split tubes. For some reason this created the back-draft problem Amervo mentioned, and the gasses and fumes worked their way through the trunk back into the car interior.

Extended the splitters by an inch or two (and changed their angle outward a bit) and the smell is gone.

stop driving backwards?

Thats an option.

But I've only got 1 gear....reverse? Should I route the pipes out the front grill?

Rommel! What else you up to my friend??

Not much, just getting ready for the new baby. Haven't had much time on the car, hoping to get the exhaust issue figured out before I have to put here in storage for 3 years. Can you send me a picture of your exhaust out the rear, like to see what you've got.

Thanks,
Chris

no really.. this needs to be fixed anyhow and it will solve your problem

Well, finally had a chance to work on the car. I checked the entire system, and the only leak was just infront of the mufflers where the band clamps connected the front X pipe to the mufflers. It was a little leak at the connection points, and the only way to fix it would be to weld the pipes, and I want to be able to break the system down, so I didn't do that. I did notice that under the rear valance, I had 2 major holes in the car body. First was where the car had been hit in its earlier life and never fixed right. The second was on the driver's side right where the exhaust pipe dropped out. It was the inner body panel just behind the wheel well. Both holes vented directly into the trunk. For a quick fix I siliconed some sheet aluminum to them, since fixing would require disassembly of the rear end which I'm not up for right now. After a short ride it seems to have fixed the problem. I'll give her a few more rides before I call it good....next step would be extending the rear pipes.

Thanks for all the help!

You can seal up the exhaust pipes with high temp silicone. As long as it's behind the X pipe it should survive.

I'll give it a shot.

Thanks Vikki.