Do exhaust fumes still enter through the open rear window

[pag04]

On my 2004 Limited and my 2014 SR5, when the rear window was down the rotten egg smell of exhaust fumes would enter through the opening. This especially happened when accelerating.
Did Toyota manage to fix this on the 2025 4Runner?

 

[ArthurKotb]

As long as the exhaust pipe comes straight out the back the fumes will curl up behind the vehicle. When we had station wagons instead of SUVs the exhaust was curved to be behind the rear wheel(s), which solved the problem. You could get an exhaust extension to do that.

 

[88Center]

I second what Arthur said. Nature of the beast with SUVs, especially.

'

 

[ArthurKotb]

Wow, super nifty pics :nod:

 

[Getbusylivin]

Hi all,
Interesting! I’ve noticed this as well, with my 2019 Ltd. I smell it more when idling/coasting downhill, for instance.

Steve

 

[NB-4Runner]

Even with the side windows rolled down?

 

[ArthurKotb]

Even with the side windows rolled down?

With the door windows rolled down it will change the airflow around the car. Above 45 mph it's going to impact your gas mileage negatively. The amount of exhaust fumes entering the cabin with all the windows down would probably be low because of the change in airflow.

 

[lpsoldia311]

I believe the 3rd gen 4runner (96-02) was the last generation that had the downflow spoiler that specifically addressed this issue. I believe it was mainly for mileage purposes to avoid the low pressure bubble forming behind the car as shown above, but it also had the great side affect of pulling the exhaust fumes away from the rear when driving normally. On my 2000 I can roll down the rear window and never smell fumes, my 5th gen I can generally only smell them when I hit hard on the gas. Never seen any aftermarket spoiler options for any 4th/5th 4runners either, but that would be nice if simplistic enough.

 

[Mark4runnar]

As long as the exhaust pipe comes straight out the back the fumes will curl up behind the vehicle. When we had station wagons instead of SUVs the exhaust was curved to be behind the rear wheel(s), which solved the problem. You could get an exhaust extension to do that.

I have a 14 ltd - exhaust out the back, and a 23 trd pro exhaust out the side.....the 14 is worse, but we still get exhaust gases when the rear window is down.....
open the sunroof / windows - that helps a bit

 

[tpetsch]

Balance Cabin Pressure: Open the front windows a crack and set your control to Outside Air with the fan on. This forces a continuous flow of air from front-to-back, creating a positive pressure zone in the cabin that pushes air out, preventing the exhaust from being sucked in.

Avoid the "Rear Only" Configuration: Opening only the rear glass (or having certain sunroof configurations open) actually amplifies the vacuum effect by acting like a chimney.

 

[Lemming]

On my 2004 Limited and my 2014 SR5, when the rear window was down the rotten egg smell of exhaust fumes would enter through the opening. This especially happened when accelerating.
Did Toyota manage to fix this on the 2025 4Runner?

Im have Gen4 that does this quite noticeably, especially under acceleration, but it stinks all the time. just picked up a gen6 and I smell nothing., Maybe my sense of smell is fried from my gen4?

 

[ArthurKotb]

Im have Gen4 that does this quite noticeably, especially under acceleration, but it stinks all the time. just picked up a gen6 and I smell nothing., Maybe my sense of smell is fried from my gen4?

Mine did that until I replaced the rubber gasket around the rear window. Now it will do it on a hard acceleration (like when new) but not just zipping along. Replace those gaskets. They're really easy to replace.

 

[DAW89446]

On my 2004 Limited and my 2014 SR5, when the rear window was down the rotten egg smell of exhaust fumes would enter through the opening. This especially happened when accelerating.
Did Toyota manage to fix this on the 2025 4Runner?

Opening all windows when dropping the tailgate window allows enough airflow out the back that I don't detect exhaust fumes entering into the cabin. And with all windows down, on a nice spring or autumn day or evening, it's a quite pleasant ride through the country side with minimal noise and zero buffeting.

 

[DAW89446]

On my 2004 Limited and my 2014 SR5, when the rear window was down the rotten egg smell of exhaust fumes would enter through the opening. This especially happened when accelerating.
Did Toyota manage to fix this on the 2025 4Runner?

Opening all windows when dropping the tailgate window on my '18 allows enough airflow out the back that I don't detect exhaust fumes entering into the cabin. And with all windows down, on a nice spring or autumn day or evening, it's a quite pleasant ride through the country side with minimal noise and zero buffeting.