Snow-blocked tailpipe, CO danger

This may be a timely question, given the round of winter storms 1/2 the country has had in the past week.

I drive a 2011 Ford Edge, 3.5L V6 AWD. After driving around for 30mins with my two small kids in the car tonight, I noticed that one of my two tailpipes was packed solid with snow… I must’ve backed into a snowbank at some point. The other tailpipe was completely clear. I didn’t notice any lack in vehicle performance, and no one seemed to have any symptoms of carbon monoxide poisoning in the car, so my HOPE is that the blocked exhaust gasses simply found their way out through the other tailpipe that was open.

I found an OEM diagram for the exhaust system for my car:

The exhaust setup features a single trunkline from the engine that passes through a catalytic converter, and then T’s off to two separate mufflers and corresponding tailpipes. So it’s not true dual exhaust (the 3.7L Edge Sport does appear to have a true dual exhaust setup, with two exhaust trunks originating from the engine…but that’s not my model).

Anyway, I was happy to see that I have the “false” dual exhaust setup that I have, as it looks like for that system the exhaust could just push through the single pipe if the other were clogged. But I’m not sure if that’s how it would work? Does anyone have an idea?

I’m worried I may have subjected my young kids (1 & 3) to CO in the car cabin (including idle time while I cleaned the car of snow). But maybe that didn’t happen, I just don’t know. I certainly will check both tailpipes from now on before embarking out, particularly during major snow events and/or backing into snow banks.

If one of your tailpipes was totally blocked, and you didn’t have the crossover pipe that mixes both ‘sides’ of the exhaust to come out both pipes, it’s likely you would have noticed your engine running like crap, it may not have even started, or it might have just ejected the snow plug at the first start.

In your case since you have the crossover setup, the exhaust likely just all came out one pipe. You might have noticed it at higher RPMs feeling sluggish. Since the exhaust system is sealed, you’d pretty much have to blow a seal or pop something loose from the back pressure before exhaust could enter the cabin. The engine’s control unit would probably have noticed and turned on the ‘check engine’ light too at higher speeds. A lot of cars have dual exhausts these days more because it’s “fashionable” than necessary. Since it’s winter (and with your kids in the car), you were probably babying your car and the extra back pressure found an outlet through the single unblocked pipe.

Now there have been stories of people falling asleep in running cars and dying like this, but it’s usually because the exhaust system is in poor repair or they parked in a snowbank in such a way that instead of fresh air coming it, that the HVAC intake is sucking exhaust fumes being trapped by the snow around the car.

I backed my car into a snow bank years ago (single exhaust). After work, it would start but immediately die…lesson learned.

I saw a car yesterday, dual exhaust, one pipe clogged with snow, the driver was passing everyone in sight, so no dirveablity problems for them. Possibly the same setup on that car and if the exhaust system is sound you need not worry about CO in the cabin imhop.

No harm no foul. Go forth, do good. The exhaust just went out the other pipe. Now if you are stuck in a snow bank and the pipes are blocked, the exhaust can seep under the car and inside the cabin, but the kids are fine and you won’t be arrested.

When I stop at a stoplight I sometimes look at the exhaust system of the vehicle in front of me. I’ve noticed that there’s a lot of vehicles on the road which seem at first glance to have two exhaust pipes, but in actuality they only have one, and the two visible pipes extend to the rear from a common source.