Exhausting and gas fumes

WZ JUNK · November 17, 2017, 08:11:11 AM

I just made a 600 mile round trip in the 54 Chevy with my brother. The dual exhaust tips end right below the bumper. The firewall is sealed and the floor of the car is sealed tight. It is cooler weather, so most of the trip was made with the windows up. It seems to be fine, with no exhaust smell during normal driving, but when you slow down or vary the engine speed up and down, you get a whiff of exhaust smell in the car. This is not a new problem, and I have checked and sealed every possible place that I could have a leak. My brother is speculating that the odor is coming back through the trunk. He thinks I need to set the exhaust tips longer or direct the exhaust to the side of the car. He also suggested taping the trunk lid seam and see if that makes a difference. I think I will tape the trunk lid opening and experiment with that idea and adjust the tips longer today.

Do any of you thoughts?

John

crdnblu · November 17, 2017, 09:02:40 AM

I don't recall your '54 build; what heater/AC system do you have? Also, what is the condition of the trunk weatherstripping?

enjenjo · November 17, 2017, 09:25:10 AM

Sounds as though it's as well engineered as a Ford Explorer.

https://jalopnik.com/ford-offers-to-repair-your-possibly-carbon-monoxide-lea-1819453530

UGLY OLDS · November 17, 2017, 12:04:59 PM

They are getting kind of scarce now , but this was an issue with "Dutch-Door" equipped Astro vans for a long time ....The fix was to adjust the rear door & hatch strikers for a closer fit .....This was also supposedly the "non-published" reason the manufactures & up-fitters stopped putting opening rear door windows on vans .....

Bob..

WZ JUNK · November 17, 2017, 12:08:27 PM

Quote from: "crdnblu"I don't recall your '54 build; what heater/AC system do you have? Also, what is the condition of the trunk weatherstripping?

It has Vintage Air heating and cooling. Lines all pass through a special bulkhead fitting on the firewall. The only other openings on the firewall are for the GM cable throttle linkage and the steering column. Both of those are sealed.

I think I will replace the trunk seal even though it is new. There are at least two designs and I believe I will try one of the others.

John

kb426 · November 17, 2017, 12:39:07 PM

If taping the trunk seam doesn't cure it, how about where the rear fender wells attach to the quarter panels? Obviously this has to be caused by vacuum from movement but there's a million cars with exhaust just like yours. Have you had Sam crawl all over it to see if you missed something? How about hooking a strong shop vac to a vent window and see if there's any kind of leak around the rear seat or package tray area?

Charlie Chops 1940 · November 17, 2017, 07:52:21 PM

Get in the trunk and start up one of your famous Cuban cigars and have your wife look for leaks.....

WZ JUNK · November 17, 2017, 10:16:16 PM

Quote from: "Charlie Chops 1940"Get in the trunk and start up one of your famous Cuban cigars and have your wife look for leaks.....

I gave up the cigars at least 3 years ago and I miss them. This might be a good excuse to have one.

Thanks Charlie.

John

Harry · November 18, 2017, 07:52:37 PM

The GMC motorhome boys check for leaks by putting a big fan inside and running soapy water over the unit.

UGLY OLDS · November 18, 2017, 11:03:11 PM

Quote from: "Harry"The GMC motorhome boys check for leaks by putting a big fan inside and running soapy water over the unit.

THAT'S ^^^^^^^^^^^^^^^^^^^ Doin' some thinkin' :!: :!:

Bob..

WZ JUNK · November 19, 2017, 07:40:41 AM

Quote from: "Harry"The GMC motorhome boys check for leaks by putting a big fan inside and running soapy water over the unit.

I plan to tape the trunk and then take the wife for a ride this afternoon to see if she can detect the odor of the exhaust. She is very sensitive to such things. (her being sensitive to odors and me being stinky has made for an interesting 50 years) On the return trip home I will untape the lid for reference to verify that it is leaking.

I might try pressurizing the car to look for the leak. I know that they do something similar when they check houses for leaks.

John

58 Yeoman · November 19, 2017, 08:01:07 AM

Way back in the late 60's early 70's when I worked at a Ford dealer, we had a gadget that we would set on the seat, then close up the car. We would then go around all the windows, etc. with what looked like a timing light, and watch the gauge on it to see where the leaks were. Do they still make those?

idrivejunk · November 19, 2017, 03:34:11 PM

Turning the heat / AC blower on high and using a spray bottle of soapy water was one thing they taught in GM wind noise and water leak training. Works on windows as well as it does on tires.

I like tailpipes that exit on the side at an angle because it sounds better. Perhaps if yours exit at the rear, the air eddy on your particular rod's shape lets gasses tumble around near the car somewhat, rather than being fully swept away.

You asked for thoughts, there's mine.

WZ JUNK · November 19, 2017, 05:02:02 PM

I taped the trunk lid shut and I took the wife for a drive. With the lid taped, you could not smell and exhaust in the car. I took off the tape and the fumes came into the car. Then I retaped the trunk lid and the smell did not come back. So it is the trunk lid seal. It has a new Steele Rubber seal on the trunk but it is not exactly installed the way that Steele instructed. I will rethink the situation.

Thanks for the input.

John

idrivejunk · November 19, 2017, 05:15:49 PM

The good old dollar bill test could help you confirm that your seal fits properly. You know, where you close the lid with a slip of paper over the weatherstrip... to see how much effort is required to pull it out, thereby indicating how much tension is on the seal at a given spot.