Chasing exhaust smell in 240 cabin

[Jaymanbikes]

Update, I used the smoke machine and turned the lights off in the garage and used a flash light to see if I could find the leak.  I noticed it was pouring in under the vinyl on the rear shock towers.  I pulled the vinyl back and will run the machine again today.  While I was doing this I removed the plastic interior panels (again!)to make sure the source wasn’t under them and the smoke wasn’t just being diverted.  My guess is there are bad panel seams.  

[Jaymanbikes]

1 hour ago, madkaw said:

Not apparent because you couldn’t tell from what direction ? Was it coming from the rear hatch area ? Have you sealed that hatch panel ? It can be tough to tell . Usually if you don’t see it right away it will make it hard to determine exactly where it comes from 

Yes I sealed the hatch panel.  See my update.  I think I’m getting closer.

[texasz]

On 2/19/2023 at 6:36 AM, 87mj said:

If it were me, I would get some seam sealer and remove the inner plastic panels and seal as far up the wheel arch as possible and along the back to the other side.  I would also check the antenna grommet hole and caulk that.   I would also remove the rear panel on the hatch and buy some of that over priced foam sound deadener (the name escapes me now).  Remove the adhesive only at the contact areas of the panel and stick that to the rear hatch.  Then any fumes making their way past the rear hatch gromets and rear hatch latch have no where else to go. Then put the hatch panel over the top of that. You will not be able to see the sound deadener.

Then if I still have fumes, I would know they are coming from the rear hatch or the taillights.  Then I would probably unbolt the rear hatch piston so the hatch would receive equal pressure on both sides against the weather strip (just as a test). Then if it goes away, you found the leak.  Please give us an update. 🙂 

Dynamat is the big name brand you may be thinking of.

 

On 2/19/2023 at 8:17 AM, Jaymanbikes said:

Update, I used the smoke machine and turned the lights off in the garage and used a flash light to see if I could find the leak.  I noticed it was pouring in under the vinyl on the rear shock towers.  I pulled the vinyl back and will run the machine again today.  While I was doing this I removed the plastic interior panels (again!)to make sure the source wasn’t under them and the smoke wasn’t just being diverted.  My guess is there are bad panel seams.  

@Jaymanbikes please post pix/video, I'm very curious about exactly where you are seeing this coming in from.

 

[inline6]

On 2/19/2023 at 9:17 AM, Jaymanbikes said:

Update, I used the smoke machine and turned the lights off in the garage and used a flash light to see if I could find the leak.  I noticed it was pouring in under the vinyl on the rear shock towers.  I pulled the vinyl back and will run the machine again today.  While I was doing this I removed the plastic interior panels (again!)to make sure the source wasn’t under them and the smoke wasn’t just being diverted. 

I am interested to see what you find.  I am not quite following what you mean by "I noticed it was pouring in under the vinyl on the rear shock towers."  Can you elaborate?  

My contribution, for what it is worth:  I found that brand new tail light gaskets did not seal air tight on my first Z.  The tail lights commonly develop waves in the mounting flange, so that where the flange contacts the body there are ripples.  When I installed new gaskets and bolted the tail lights in place, I didn't give it a second thought.  However, what was probably a few years later, when I was chasing the source of exhaust smell, I pulled the left tail light and saw "exhaust staining" on the paint under the where the gasket met the body.  Looking closer, there were clearly air gaps between the body and the gasket.  So, I put some 3/4" wide, 1/4 or 3/8 deep closed cell foam rubber weather strip on the body of the car where the gasket sits, and then bolted the tail light (with factory gasket still in place) to the car.  This made a notable difference in the exhaust smell.  It did not eliminate it, but I didn't do the same treatment to the right side tail light (still - many years later now).  And the car I am talking about has hatch vents, so I assume there will always be a bit of exhaust smell when I drive with only one window down.

The other thing worth mentioning is while I thought my hatch sealed all the way around on my car, I found out it did not by observing snow melting off of the car.  After a light snow, the car was parked and heating up in the sun.  I noticed that snow melted at the gap between the hatch and quarter panel on each side of the hatch panel in areas about 6-10 inches back from top edge of the hatch panel.  It was apparent that heated air from inside of the car was escaping there and caused the snow to melt.  Testing with small bits of paper, I confirmed that the panel was not touching the main hatch weather strip at those locations (only for a few inches).  

Those are what I found when I went looking.  The car I am restoring now has vents on the quarter panels instead.  When it comes time to do the assembly, I'll be investigating the same areas closely and addressing any issues I find.

Edited February 20, 2023 by inline6