Rear Window Open and too much exhaust smell

[mhbarber]

It's a normal byproduct of hard acceleration and the chemistry involved in catalytic converters. In short, the combustion process is less than optimal in most driving situations, allowing hydrocarbons and sulfates to build up in the cats. As temperatures increase or you get a sudden heavy burst of hot gases, a reaction occurs (by design) that converts the hydrocarbons to sulfur dioxide... releasing the rotten egg smell. 4Runners get it the worst because our tailpipes go straight out the back and we have a window that CAN be rolled down and the airflow comes up and into that window when it's down.

The best option is to have a shop bend the exit pipe to the passenger side and put a nice exhaust tip on it.

Thanks Mike. I'll look into that.

 

[harper7]

Thanks Mike. I'll look into that.

I had mine modified to side exit and it eliminates about 90% of the smell. With other windows open I can't smell it at all unless I'm really romping on the gas.Here's the thread on it............ http://www.toyota-4runner.org/5th-gen-t4rs/87269-side-exit-exhaust.html

 

[Antman]

Simple way to demonstrate the "low pressure behind the vehicle" point. Roll down your rear window and tape a piece of clear plastic across the entire opening. Go for a drive- keep the sunroof and the door windows closed.

The plastic will suck in towards the vehicle at speed, not out like many would think. If you don't believe me- try it!

 

[rickwol]

The rotten smell can be offensive but its what you don't smell (carbon monoxide) that can make you sick and accumulates in your body over time. I put a battery operated carbon monoxide detector in the vehicle. No problem driving around with the rear window up. As soon as you put it part way down the alarm sounds. Can't be good for you or for your passangers be they human or animal. If I have the side windows partway down and the sunroof wide open it does not seem to be a problem. I think rerouting that tail pipe as mentioned by Harper is probably a good idea and I am going to look into that.

 

[kingpin748]

I know I should take it in, but haven't. I asked the dealership to address the exhaust smell at the 5k inspection, but they didn't find anything unusual. I would love to drive around with the rear window down, but whenever I hit the gas, the smell is terrible. My children won't ride with me when the rear window is down. Sucks.

SO now you don't have to drive your kids around and they get some exercise. Seems like a win-win situation to me.

 

[Ripsnort]

I'm typically going faster than 45mph when the back window is down. No way in hell can those fumes catch up into the cabin from the back and move through the cabin. Never have smelled a thing other than my teenagers stinky sports gear.

 

[Antman]

They don't need to "catch up", they get sucked in (provided you only have the back window open):lookout:

 

[-JD-]

What I've been curious about is how much you need to open your windows to counter the low pressure behind the vehicle .....

i usually jsut roll down the front 2 and have the sunroof vented...

 

[coldryder]

Has anyone with an SR5 or Limited had their exhaust pipe rerouted to the side? As far as I can see, the mody moulding on the SR5 and Limited hangs lower than on the Trail Ed. and thus, if you route the exhuast to the side, the tail pipe will run super low, affecting ground clearance.

Any thoughts or solutions?

 

[Antman]

Has anyone with an SR5 or Limited had their exhaust pipe rerouted to the side? As far as I can see, the mody moulding on the SR5 and Limited hangs lower than on the Trail Ed. and thus, if you route the exhuast to the side, the tail pipe will run super low, affecting ground clearance.

Any thoughts or solutions?

Here ya go.

http://www.toyota-4runner.org/5th-gen-t4rs/87269-side-exit-exhaust.html#post756308

 

[SeattleMike]

Has anyone with an SR5 or Limited had their exhaust pipe rerouted to the side? As far as I can see, the mody moulding on the SR5 and Limited hangs lower than on the Trail Ed. and thus, if you route the exhuast to the side, the tail pipe will run super low, affecting ground clearance.

Any thoughts or solutions?

Here ya go.

http://www.toyota-4runner.org/5th-gen-t4rs/87269-side-exit-exhaust.html#post756308

Dude... you posted a link to a TE.

 

[Antman]

Ooh...Well I did drive home with the rear window open and I was feeling light-headed when I posted. :jk:

Sorry bout that!

 

[Riser]

My rear window is down most of the time (dog) and I never smell exhaust fumes. I agree with the other poster, probably from other vehicles

 

[terra4r]

My 3rd gen used to have a spoiler over the rear window, it would direct air moving over the vehicle down and over the rear window to help counter the air/exhaust coming up from below the vehicle. Too bad they didn't continue this, made a big difference to the exhaust and dust coming in the back vs. my 2nd gen....

looks like this...

coming from a 3rd gen, I don't think this spoiler helped any more than the next. I would frequently smell the sulfur. I only used to smell it when i was accelerating though, I haven't smelled it in the 5th gen at all yet. I love the back window, so its just the nature of the beast IMO.

 

[rickwol]

My rear window is down most of the time (dog) and I never smell exhaust fumes. I agree with the other poster, probably from other vehicles

Ha, carbon monoxide (CO) is odorless. Get yourself a CO detector and run it in your vehicle with the rear window open and tell me what happens. I wish my dog could talk to me like yours.

 

[Riser]

Ha, carbon monoxide (CO) is odorless. Get yourself a CO detector and run it in your vehicle with the rear window open and tell me what happens. I wish my dog could talk to me like yours.

We aren't sitting in the garage with the door down :redbrick:

 

[rickwol]

We aren't sitting in the garage with the door down :redbrick:

Don't need to be. Simply moving with that window down sucks it right inside.

 

[sandwich]

This issue is very real and probably dangerous, anyone who says they don't notice it should get their sniffer checked out, or maybe clear it out with some Kleenex lol

Everytime I pick up some wood or anything that's longer than 8' and not too heavy, I open the rear window and let it hang out for the drive home. I do this instead of strapping it to the rack sometimes and of course protect the window sill with towels. Every time though I have a headache when I get home because I'm bombarded with exhaust fumes the whole drive back. Even with other windows open and I noticed it got worse with the sunroof open. Needless to say I'm going to make more use of my rack.

 

[Riser]

I am no stranger to CO detectors. I work for a natural gas company for starters and have them throughout my house. But what do I know! I will leave it to the tailgate window experts.

 

[Uneek]

Ha, carbon monoxide (CO) is odorless.

:iagree:

Took the 4Runner instead of the Tacoma to Home Depot for closet shelving with part of it sticking out the back window. The exhaust gets sucked in fast. I was feeling nauseous within driving a few blocks.

For me, the roll down window is great when stationary but not so much when driving due to the exhaust. Like when there isn't enough room to open the hatch and access the cargo area or when parked for extra ventilation.