Exhaust fumes in cabin when driving with rear window open?

[Hacksaw]

I recently did some driving with the rear window down. I seem to be getting exhaust fumes in the cabin, but I'm not positive they were from my 4runner because it was in traffic. Just wondered if others have experienced the same thing.

It probably wasn't the best design to have a rear-exiting exhaust for a vehicle with a roll-down rear window with a rear spoiler above the top of the window in any case.

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[oregonalex]

Yep. The manual says on p. 180:

Caution while driving!
Keep the back window closed. ... prevents exhaust gasses from entering the vehicle.

Same warning in my old '98 4R manual. Makes sense. There is turbulence behind the vehicle and all kind of crap could be coming in.

 

[MTN Dew]

Every gen 4 runner is that way opening front windows will help.

 

[Hacksaw]

One reason I got the 4runner rather than another Tacoma was that the 4runner could (or so it seemed) still do some pickup truck duties like carrying 8-12 foot long wood or pipe, sticking out the back window with it rolled all the way down. I'm regretting not getting a sunroof since having that opened with the rear window down would probably be one of the better ways to help push exhaust out the back.

I guess I could revisit getting a full length roof rack. Those have all been out long enough now that any initial bugs are probably addressed. Still, it's much easier to toss the long pipe/wood in the back rather than trying to tie it down to a roof rack (but maybe that is easier than it seems).

 

[Dead Horse]

Without a bed cover...When I roll the back window down on my Tundra, every single thing in the bed that's light enough to get airborne rolls right into the cab. Exhaust too, sometimes. Particularly frustrating when you learn this with two huskies that are blowing out their seasonal coat and get 200,000 lbs of dog hair blasting into the cab. Cracking the windows on the front and/or rear passenger doors makes a massive difference. Playing with which ones and how far is a game of "which way is the wind blowing and which windows will fix this today".

I suspect the 4Runner is going to be the same. Sunroof will add to the equation, but I doubt it's necessary.

 

[get.outside.75]

Pop up the sunroof or crack some windows.

 

[DangItsDen]

On my 5th gen I had a muffler shop cut and weld on a 90 degree angle tip that exited behind the rear tire. Not sure I'm going to go that route on this truck, but it was a pretty cheap fix.

 

[djw4run]

On my 5th gen I had a muffler shop cut and weld on a 90 degree angle tip that exited behind the rear tire. Not sure I'm going to go that route on this truck, but it was a pretty cheap fix.

This was the first thing I did when I first bought my 5th gen Trail edition. Not only did it fix the problem with fumes entering the cabin it looked a lot better as well. Of course our German Shepherd also thanked me. I will plan on doing the same when I trade in for the 6th gen.

 

[127.0.0.1]

with strategic venting of other windows and moon roof in specific amounts
you might be able to drive with rear window down and not die of co poisoning
but the vehicle aerodynamics have not been designed to allow safe operation while
rear window is down. never has, never will.

do not rely long term driving with it cracked or open on lack of noticeable smell,
scent-free CO can still invade the cabin and put you to sleep and cause a wreck

imho the best idea is set up the other windows and vents to feel a breeze on your
face if you must also have the rear window down while driving

 

[George]

Come on guys, just Crack a tailgate window. I had a 2007 4runner, then bought my 2025 4runner off road prem. I smoke cigarettes. I keep my the tail gatewindow down maybe an inch. Then Crack one passenger window. If my driver's window is down it blows in fairly hard, Crack the tailgate window and the heavy wind calms down. But don't Crack a passenger window with out lowering the tailgate window, this will cause turbulence. I guess driving a 4runner for 18 years has some value.
DO NOT keep that tail gate window down when on dirt!

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