1971 Duster exhaust smell in cabin after new muffler and tail pipe

[tedsweet]

that revised pipe is fine its the holes in floor that are the issues

 

[barbee6043]

I guess we are knit picking but I too, rather the exhaust blow clear from the bumper. Sometimes bumpers are new and shiny and costs $600 or so!!! I admit it is a lot better and body plugs are always a good thing!!

 

[Teratech]

The differential leak is most likely the pinion gear seal. It's one thing to have a greasy looking differential, but it way worse to have an empty differential without lube.

 

[Martin Koiryohann]

Hello all,

My 71 slant six duster's muffler was noisy, buzzing and rotted through, so I took it to a local exhaust shop to get it replaced.

They replaced the muffler and tail pipe. I paid and left. Within a couple miles the air in the cabin felt stuffy, thick and my nasal passages started swelling. I thought maybe the car in front of me had exhaust leak. Long after I passed him I still felt like the cabin had a low but constant volume of exhaust making me feel sick. I took someone else for a ride, they smelled exhaust too. Windows up or down.

I looked underneath the car and noticed the end of the new tail pipe looks like it's at a different angle than the original pipe, like it doesn't have the same curve. It also seems like it's tucked under the car more, and doesn't extended out towards the bumper as far as the original did.

Can someone confirm or post a picture of where the stock pipe ends? My suspicion is that my new tail pipe is not long enough, and/or not curved toward ground enough, and exhaust is being pulled back into car.

This was not happening before I had the work done. And currently I don't hear any audible leak, so that's why I'm focused on the tail pipe theory. Also, my exhaust manifold heat control valve is frozen, but I don't see how that could cause an exhaust leak into cabin.


Here's a pic of new pipe


View attachment 1715953211

View attachment 1715953212

CHANGE SHOP

 

[Swinger 340]

Cut the 'gooseneck' off and put a chrome A body box tip on there.

That's what I would do.... to fix it.

Tail pipe will not be long enough for a chrome tip. I also believe he has a body plug missing to allow the exhaust into the car. A station wagon with an open back window is known for this. The reason some have a top deflector.

 

[Dale Davies]

I snapped some pics from underneath while they had it on lift. Looks like I have a couple floor pan plugs missing

View attachment 1715953258

IMHO, the dobie that did the job cut the pipe off just ahead of the muffler, banged the new muffler on and welded it. If the tailpipe is a stock replacement it would be 2" to 3" too short. You would have thought the old muffler would have been leaking also and missing body plugs would have let the exhaust in.
Hard to get good work done properly now. Ethics is quickie fix and blow it out the door. I could not work like that and quit pulling wrenches. Then instrumentation in the oil patch. Dealing with numb nutz that barely graduated high school. Gave that up also as I was tired of coming home frustrated. Better at home broke but no road apples dumped on you all day.

 

[Dale Davies]

Tail pipe will not be long enough for a chrome tip. I also believe he has a body plug missing to allow the exhaust into the car. A station wagon with an open back window is known for this. The reason some have a top deflector.

Wagon tail pipes normally go out the side for that reason.
Deflector was to blow clean air over the back window to keep dust off. You have to remember there was a lot more dirt or gravel roads back then. The dust would swirl behind the flat wagon back and settle on the glass and sheet metal. The deflector aided that. My 82 Blazer had one also for that reason.

 

[Cuprum-74]

Also double check all the firewall plugs while you're at it too.
I had that problem as well. I mean it wasn't bad for me, but occasionally I had a slight exhaust smell in my cabin every time I cruised at low speeds or when I sat in traffic for more than a few minutes. It wasn't strong but it was enough to get a hint of it.
Come to find out I had a firewall plug that was dry-rotted and was about to fall out of it's place. I just RTV'ed it temporarily until I got a replacement for it at Classic Industries.

 

[Cuprum-74]

Wagon tail pipes normally go out the side for that reason.
Deflector was to blow clean air over the back window to keep dust off. You have to remember there was a lot more dirt or gravel roads back then. The dust would swirl behind the flat wagon back and settle on the glass and sheet metal. The deflector aided that. My 82 Blazer had one also for that reason.

As did my old 1984 Dodge Ramcharger... Man I miss that truck.

 

[Swinger 340]

Wagon tail pipes normally go out the side for that reason.
Deflector was to blow clean air over the back window to keep dust off. You have to remember there was a lot more dirt or gravel roads back then. The dust would swirl behind the flat wagon back and settle on the glass and sheet metal. The deflector aided that. My 82 Blazer had one also for that reason.

You are right Dale Davies, that is what we were told it was for. Where does that dust come from? From under the car or rear window truck. If you think the dust is bad, try breathing the exhaust all day. I remember as a kid, my sister and I would sit in the rear seat at the tail gate. The wagon had no deflector and we would complain of the smell. If I'm not mistaken we would also get a headache.