37 Roadmaster: Exhaust fumes in the passenger compartment

[chstickl]

As far as my experience, old exhaust systems are never 100% tight - starting from the manifold down to every junction. Nevertheless this shouldn´t lead to the strong smell I have inside, when going slow or standing with running engine. Now I saw that there is a direct path of hot air from the engine department through the inner side of the fenders directly to underneath the dashboard left and right, coming in behind the covers next to the pedals (front end frame side brace). While I took some effort to have new and tight rubbers, where the pedals go through the floor, this seems to be the reason for smell and nausea. Am I missing some part here that blocks the hot air or is that the way it used to be?

Thanks for your kind advice,

Chris

[JoelsBuicks]

Chris, the most concerning part of your post is the word nausea. This is a symptom of carbon monoxide poisoning. As you already know, engine exhaust is making its way into the cabin and this is not normal at all. I would concentrate on fixing the exhaust leaks before I would address leaks into the cabin.

If you still have that smell after going through the exhaust, you might have excessive blow-by on the rings. One thing to try is to open the cowl vent to get as much positive pressure as possible in the cabin.

I realize I've not got much to offer in solving the problem, mostly just wanted to alert you to the gravity of CO poisoning.

Joel

[egor]

Old car bodies aren't airtight. You're not going to solve the problem by replacing rubber seals. Look to the exhaust system. You're right, it's not perfectly sealed, but it shouldn't be leaking so much monoxide that it's making you sick.

[Bob Engle]

there aren't that many places to leak: Manifold to head, manifold to exhaust pipe, exhaust pipe to muffler, muffler to tail pipe. With exhaust into the passenger compartment, it is most likely the manifold to head or manifold to exhaust pipe. With the engine idling and hood open, have someone hold a rag over the tail pipe. you should easily hear the leak. Back in the day in PA. doing car inspections this was the way to check for leaks. Obviously, rusted out exhaust pipes, mufflers and tail pipes were a common problem. If there are no rusted out components, I'd bet on the manifold to exhaust pipe flange as the problem. There should be no exhaust leaks even on these old cars. Good gaskets, and clamps should keep it leak free.

Bob Engle

[Larry Schramm]

Are there any openings in the trunk area that might be sucking exhaust fumes back in the car?

[smithbrother]

Not that this is the ISSUE, but does the tail pipe extend past the bumper? I have heard of issues where it didn't, and exhaust was curling inside the bumper curve, and getting in trunk area.

I wish you well,

Dale in Indy

[Larry Schramm]

Not that this is the ISSUE, but does the tail pipe extend past the bumper? I have heard of issues where it didn't, and exhaust was curling inside the bumper curve, and getting in trunk area.

I wish you well,

Dale in Indy

Same basic thought