Exhaust getting into interior

Mopar Exhaust Systems

  1. Jack Ryan

    Jack Ryan New Member

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    I need help. 1965 300 4dr HT exhaust getting into the interior. The only thing that seems to help is running fan with windows shut and floor vents shut. Any other combination and after a short drive my clothes smell like exhaust. Thought it might be blowby escaping from valve cover breather, rerouted that into air cleaner intake but to no avail. No audible exhaust leaks before the muffler. It's possible that there are some in the muffler and tailpipe that I have not discovered. Car was quite rusty, is it possible that it is coming from the end of the tailpipe back into the trunk? Don't want to spring for a new exhaust if it is not going to fix the problem. Thanks.
     
  2. cbarge

    cbarge World Famous Barge in a Budget FCBO Gold Member

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    If you have holes in the trunk,or the trunk weatherstrip is petrified or missing you will get fumes in the cabin with windows down...Kinda creates a vacuum.
    Holes in the floor will do the same thing especially if the top of the mufflers have holes that you cannot see.
    I always run the end of the tailpipes 2-4 inches past the bottom of the rear bumper too.

    hope this helps
     
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  3. 4spd300J

    4spd300J Member

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    As in the above post, any gap in the trunk seal will draw enough fumes in the cabin to make it seem like the exhaust comes out of the dash. That's why wagons ran the exhaust out the sides instead of straight out under the bumpers.
     
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  4. The Goose

    The Goose Senior Member

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    Forget stinky clothes - this can kill you. You can smoke bomb the exhaust and check for leaks. We do that to check for leaks in cabs on heavy equipment. It’s not as big a deal today as back in the good ol days. Back then Rusty pipes cost thousands of lives. Be careful bud...
     
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  5. 1970FuryConv

    1970FuryConv Senior Member FCBO Gold Member

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    If you suspect a plugged muffler, put a vacuum gauge on the intake and slowly increase engine speed. Vacuum will drop toward zero from an idle vacuum of around 17hg. Old mufflers can look OK from the outside but have a lot of rust from condensation on the inside.
     
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  6. cbarge

    cbarge World Famous Barge in a Budget FCBO Gold Member

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    ...Or plugged by mice nests..
     
  7. Jack Ryan

    Jack Ryan New Member

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    Hey thanks all, gives me someplace to start, actually lots of places to start. Has not killed me yet, only a little dizzy.....kidding.
     
  8. cbarge

    cbarge World Famous Barge in a Budget FCBO Gold Member

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