PSA for anyone that drives with their rear window down

[Something_Awesome]

For those of you that do not know, when you have your rear trunk window down a tornado effect occurs that sucks air in to your cabin from the rear. This is also the case even if you roll down your front windows in conjunction with the rear trunk window.

This phenomenon is actually very easy to prove. Drive over a small puddle and sprinkles of water will get sucked in to the cabin from the rear. However, it never occurred to me that this creates a carbon monoxide hazard (thanks to AutomotivePress for pointing this out). I have a child car seat in the back for a 1.5 year old. Luckily, I have only rolled the rear window down with him in the vehicle twice, and for short drives. I also have the TRD Exhaust which would reduce how much carbon monoxide gets sucked in since it has a side outlet. But still, the reduction is likely not enough of an amount that would make me comfortable. And for what it's worth, I think you'd really need a lot of exposure in this manner to lose any brain cells. Could be wrong though.

I love this feature, and is one reason out of many that I did not want a 6th gen. But I'd not roll down the rear window anymore if there is someone in the back seat while driving. The front passengers should be fine though. On a hot day, I'd rather roll down the front windows and the rear trunk window. Having that rear window down automatically makes it feel like 10 degrees cooler. It's incredible.

 

[tokyo rebuilt]

Seems a little tin-foil hat to me honestly. Plus you live in L.A; I highly doubt driving with the back window down is posing any more of a risk than you walking down the street or at an outdoor mall.

 

[USStrongman]

There are way too many factors to say that this is a potential health hazard. Is your fan circulating? Is it blowing only? Are other windows open? If so, which ones? What speed or speeds are we talking about?

Yes, there is a vortices that occurs behind all vehicles as the air tries to repurpose itself into a non moving entity. There is usually a vacuum effect that occurs that can pull air into the rear window when down, by itself usually. However, only a very tiny portion of the air that is being vorticed and with that, a tiny portion of the CO2 being emitted into the atmosphere is included in that.

 

[2021nightshade4x4]

Now a real problem is my old Dodge that had an exhaust leak and no “recirculation” setting on the HVAC.

I kept wondering why I always got a headache less than 10 minutes from starting to drive that car. It wasn’t strong enough to smell, but I don’t know how many brain cells I lost before I put two and two together.


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[DallasTRDPro]

I'm more worried about the soot on my headliner.

 

[BlackWorksInc]

■Caution while driving
Keep the back door and back window closed while driving. If the back door
or the back window is left open, the back door may hit nearby objects while
driving or luggage may be unexpectedly thrown out, causing an accident.
In addition, exhaust gases may enter the vehicle, causing death or a serious health hazard. Make sure to close the back door and back window
before driving.

Has been at the end of the power rear window instructions in the owner's manual for at least 3 generations IIRC (it's there for 4th & 5th gens for sure, haven't bothered to check a 3rd gen, but have no doubt it's there given exactly what the OP describes has been a thing since old 70's & 80's station wagons).

Mainly the biggest issue is more just CO poisoning since you wouldn't notice it and would assume that with all the windows open it should provide plenty of airflow. Though it takes a relatively small amount of CO to start affecting people; so it's something to keep in mind and be aware of.

 

[Whippersnapper02]

I usually have it down when I drive too. It's another reason why I want the TRD exhaust because it moves the outlet to the side.

 

[spartacus]

I've driven with all windows down and the sun roof open and seems to be fine on back country roads. There seems to be plenty of air flow to dissipate the exhaust.

 

[5thToy]

I'm more worried about the soot on my headliner.

This, and it isn't news that air gets sucked in with the back window down.

Opening the sunroof helps with airflow in conjunction with the other windows.

 

[rageandlove]

Put on a TRD Pro exhaust which sends it out to the side. Or get a muffler shop to cut and weld a 90 degree pipe on and do the same thing as the Pro exhaust for less.

 

[emmantik]

I'm more worried about the soot on my headliner.

I agree! Driving with the rear window down eventually leaves a dark film on your headliner. Though I recently swapped to a TRD side exit exhaust. The sulfur smell is not as noticeable as with a straight back exit - though it is still there.

 

[Brandonium]

Hell yeah. I still drive with it down all spring, fall and some of winter. I just had to make a habit of hitting the headliner with a shop vac and brush attachment every weekend to mitigate that. First year of driving I did not do this and it was disgusting.

As to the CO hazard, I have known this for some time but it has never been an issue. I still count using my fingers however so maybe I would never know!

I'm more worried about the soot on my headliner.

 

[2021nightshade4x4]

I agree! Driving with the rear window down eventually leaves a dark film on your headliner. Though I recently swapped to a TRD side exit exhaust. The sulfur smell is not as noticeable as with a straight back exit - though it is still there.

Doesn’t the sulfur smell mean your cat is failing or has gas in it?


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[Something_Awesome]

Seems a little tin-foil hat to me honestly. Plus you live in L.A; I highly doubt driving with the back window down is posing any more of a risk than you walking down the street or at an outdoor mall.

It Sucks the carbon monoxide to the back half of the vehicle. Like I said, you can test this for yourself. You can drive your vehicle and observe it with water.

 

[Gamma Ray]

Someone should get a carbon monoxide detector and measure carbon monoxide levels in these conditions.

And regarding the manual part about the back window being down, I have all of my stuff secured. If I have something that's not secured, then my windows stay up. I even have one of those Rago toilet paper holders, and I have a rubber band around the roll all the time for this reason.

 

[IslandJim]

Not only CO2, but sand! Here in Florida we only have sand, not dirt. Driving down my friends unpaved driveway got a huge amount of sand in the back window. Going slow at that! Only drive with it down sometimes, just about a few inches.

 

[2021nightshade4x4]

Someone should get a carbon monoxide detector and measure carbon monoxide levels in these conditions.

And regarding the manual part about the back window being down, I have all of my stuff secured. If I have something that's not secured, then my windows stay up. I even have one of those Rago toilet paper holders, and I have a rubber band around the roll all the time for this reason.

Some of the Kidde Nighthawk models, about $30, have a 9V battery backup if you want to measure levels up front, or use the outlet in the back if you just want to get a reading at the window.


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[TRD PANTHER]

I usually just run the back window down 6-8" and open the sunroof. You get that convertible feeling without all the wind turbulence in the car. I can drive for a long time like this, especially on summer nights.

 

[2021nightshade4x4]

I usually just run the back window down 6-8" and open the sunroof. You get that convertible feeling without all the wind turbulence in the car. I can drive for a long time like this, especially on summer nights.

I am thoroughly impressed with the lack of buffeting when only the back window is open. You can’t even hear the difference:


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[4RunnerAquasport]

This has been discussed on numerous occasions over the years. Owners with young children or pups who like to ride w the cargo rolled down, will have an exhaust shop turn the tail pipe right behind the right rear.

This seems to be the only solution. Of course when your stopped the fumes can and do get in, but that can happen w most vehicles.