Burning rubber smell right rear fender well.

[TOY2G]

On my way to DC today I noticed the very distinct smell of burning rubber from the rear of the truck (2013 SR5 @ 34k). I sniffed around and it seams to be the worst at the right rear.

I checked the tire pressure all the way around, check all the rear bushing, shock, tires for heat or sign of wear and found nothing.

Filled her with gas and hit the road, but when I mentioned it to my wife she said "yea, I've been smelling that for months".

Today's driving conditions, light rain, 70-75 60 degrees cruise control set.

At my last fill up the smell was still there and just as strong, but if I wait about 10 min it goes away.

So if it's not rubber I can see or feel, it has to be rubber that is hidden, I suspect outer axle seals, anyone else?

I know these guys have has the same smell...
[MENTION=86190]Alex T4R[/MENTION]
[MENTION=52619]Whiplash Willy[/MENTION]
[MENTION=80279]Socalrugger[/MENTION]

 

[1engineer]

Nathan several of us get that smell every now and then. There are many threads out there talking about it but to my knowledge nobody has identified it. I personally have checked several times and I frankly have no idea what it is. I do know though that after 50K miles whatever it is does not seem to cause any issues. I had it on my '11 SR5 and now my '12 TE. I have a total of 116K miles of seat time between the two and I still get that smell occasionally. Wish I could help but I don't even worry about it anymore.

 

[Crushinator]

My '14 has it too. I have my daughters car seat in the passenger side rear and when I get her out I notice the smell. Figure it was normal after reading the threads on here.

 

[Raven]

Same here - sometimes it fights with that wonderful new car smell!
2015 TE, two weeks old.

 

[4runner4MeCarp]

I have smelled this as well. At first I thought it might be the new lift and tires but I cannot find any indication on where this smell is coming from. I have 2k on the truck now and it only appears after a long road trip/ drive. I think it might be from the exhaust rubber hangers heating up but I cannot be positive. Anyone else found any possible culprits?

 

[bigandtall]

It could be grease from a u-joint slinging onto the exhaust system. It has a similar smell when it burns.

 

[TOY2G]

It really is perplexing. I cannot help but think something is wearing prematurely. Axle seal too tight?? Shock bushings cycling too much???


Who knows, I'm sure we will find out well after the warranty is up.

 

[mace.]

I would get that smell every once in a while too. Obviously pulling into the garage made it seem a lot worse. I think it may have occurred more when it was wet out. I haven't noticed it since I did my diff breather extension. Not sure if there's even a possible correlation there or if gear oil even smells like burning no rubber when it gets hot.

 

[ATL4R]

Nathan several of us get that smell every now and then. There are many threads out there talking about it but to my knowledge nobody has identified it. I personally have checked several times and I frankly have no idea what it is. I do know though that after 50K miles whatever it is does not seem to cause any issues. I had it on my '11 SR5 and now my '12 TE. I have a total of 116K miles of seat time between the two and I still get that smell occasionally. Wish I could help but I don't even worry about it anymore.

I could be smelling something different, but I've always chalked this up to grease from slip yoke and ujoints flinging onto the exhaust piping. You can see the dots on your exhaust tubing where these grease spots occasionally land and burn off.

 

[V8PoWer]

Ive been keeping track of this smell too and have notice that everytime i drive like a maniac(high reving) rushing to get home, i have that burning smell once i pull into the garage. But it is just city driving, not enough high speed to fling any grease around.

 

[Whiplash Willy]

I experience the smell every day, as I drop my kids off at daycare. The daycare is on top of a hill, so I am always putting some load on the engine, then getting out, and going over to the rear pass side door to get my daughter out of her car seat.

Along with the smell, my muffler ticks, snaps, crackles, and pops like crazy, once the 4runner has been turned off. I have been under the 4runner many times with a flashlight, while the smell was occurring, but could never find anything on or around the exhaust or muffler that would cause this.

I have noticed the smell only occurs after I have put load on the 4runner, like driving through a parking garage, or driving up a hill. Out of curiosity, I measured the muffler's temp with an IR thermometer after driving up a hill, and it was around 320*F. During normal operation at idle it is around 215*F.

I have read threads on the FJ Cruiser forums about the same smell. One guy even cut open a muffler and this is what he found:

Thread: Anatomy of the OEM Muffler. - Toyota FJ Cruiser Forum

Had a little fun today with the cut off wheel and air chisel!
I wanted to see what was inside the OEM muffler. Surprisingly it is dual layer wrapped. The pipe diameter is a weird non standard OD size.

I was also surprised to see no sound dampening material, just holes drilled and stamped in the baffles and partitions in the muffler chamber...

I was under the assumption that this was a decent muffler system and determined it was adequate for the FJ. Upon opening up the muffler shell, my opinion has changed. I`m sure the engineers find it adequate and the bean counters find it cost efficient but from a flow characteristic it is pretty lame.
I can understand how this can get very hot under load while trying to force the hot exhaust gases thru the perforated tube and reflecting sound waves in between the interior partitions... Lame...
OK, just my 2 cents worth...

So after much obsession, I believe is normal, and most people just don't notice/care about it. Here is my conclusion on the smell.

1. The Smell is from the inefficient/poorly designed muffler, that can get super hot, when even a moderate load is put on the engine.

2. I have never found any trace of anything burning on, or around the muffler, or exhaust pipe, so I believe that is just the smell of muffler itself at 320+*F.

3. Replacing the stock muffler with a straight through design one would eliminate the smell.

 

[Cinic]

I hate to revive an old thread, but this was the most recent one addressing this smell.

Is there any chance this is the smell of the differential oil getting warmer than usual and the odor venting from the breather? Everyone seems to notice it under load and the differential would be doing more work at this time. And it is open to atmosphere.

I changed the gear oil in there today and that oil smells like no other regular oil and could easily be construed for something burning.

Just a thought...

 

[TOY2G]

I hate to revive an old thread, but this was the most recent one addressing this smell.

Is there any chance this is the smell of the differential oil getting warmer than usual and the odor venting from the breather? Everyone seems to notice it under load and the differential would be doing more work at this time. And it is open to atmosphere.

I changed the gear oil in there today and that oil smells like no other regular oil and could easily be construed for something burning.

Just a thought...

That's not a bad idea, but I cannot imagine someone mistaking the distinct smell of burning gear oil with rubber. Burning rubber and gear oil both have a very VERY distinct smell, but the smells are not similar to each other.

I think there is a reason every says they have a "burning rubber" smell and not just a "weird burning" smell. The smell is clearly rubber

 

[Whiplash Willy]

I am still experiencing the Burning smell every day, and it has been going on for the last 30k miles. I still can find no trace of anything actually burning, and still believe it is just the smell of the muffler itself getting very hot during load (320*F) due to poor design. The only thing I ever see on my exhaust is road grime.

I bet that nobody with an aftermarket exhaust or muffler experiences this smell. Gear Oil does smell bad, but the burning smell I experience is very different to Gear Oil.

 

[3wbdriver]

Could it be heat transfer to the rubber grommets that isolate the exhaust from the frame hangars?

 

[Whiplash Willy]

Could it be heat transfer to the rubber grommets that isolate the exhaust from the frame hangars?

Theoretically that makes sense, however if they got hot enough to produce a burning smell, you would think they would show some sign of burning. Mine look normal. I have checked for signs of stuff burning all around the exhaust, and haven't found anything.

I almost want to swap out my exhaust just to get rid of the smell and know for sure what the smell is.

 

[1engineer]

Theoretically that makes sense, however if they got hot enough to produce a burning smell, you would think they would show some sign of burning. Mine look normal. I have checked for signs of stuff burning all around the exhaust, and haven't found anything.

I almost want to swap out my exhaust just to get rid of the smell and know for sure what the smell is.

I had the smell on my 2010 SR5 and 2012 TE. I do not have the smell on my 2015 SR5. Coincidence? I think not...

 

[Ebbsnflows]

My 2005 does the exact same thing. It's driven me crazy for years. I always thought..."If there's really something burning...after 5 yrs of ownership and 80k miles...it would've broken/melted/disintegrated by now".

Glad to hear that other generations do it as well.

 

[itsdchz]

Thank GOD!
I am not alone in this. I have noticed the same thing, and usually attribute this to my crazy pole position driving, but now, thank goodness I am not the only one.

I am wondering if it is a coating on the exhaust, as I would imagine if it was the differential, the relocated breather would stink up my cabin instead....

I would love to know an answer, but if it is the same with everyone, it has to be something that heats up, or circulates, to get the juices flowing..

 

[415T4R]

For the first month or so, I thought it was other cars on the road, driving inefficient. Now after seeing this revived thread, I am glad to see I am not the only one. Thanks guys, loving the crowd sourced info on this this thread.

I might just have to swap out for a Flowmaster to solve this "problem" lol