In the past few months my 89' 4runner SR5 V6 has developed a burning rubber smell that gets much worse when it's "stressed" (driving up hills or anything that requires more than light throttle). It does it in 2wd and 4wd, hubs locked or unlocked.

I replaced the balancer already, it was bad, and put all new belts on and tensioned them properly. No squeals there and the belts don't get hot.

I looked for hoses touching the exhaust or anything melting on the exhaust anywhere, didn't see anything.

It smells like it's coming from the bottom of the motor or the driveline somewhere. It doesn't really smell under the hood so much.

Oh and the tires aren't rubbing, I checked that too.

I've tried looking for the smoke and smelling for it but it's driving me nuts. I really want to get this figured out before the top comes off for the summer, or before it catches on fire.

Anyone have any ideas? anything common?

 

Is it a 5 speed... Not your clutch is it?

Or... oil dripping onto the hot exhuast.. It has a distinct smell. I wouldn't say it smells like rubber but

 

I'm driving a Jeep WJ right now with a 4.0 and it has a bad valve cover leak. The oil never comes close to the exhaust but has coated the outside of the engine block.

When I'm running it hard or idling for an extended amount of time I smell it. Maybe this is what you are smelling? Got any nasty oil leaks?

 

Take a look at the coolant in your radiator...
My motorcycle had pretty old coolant liquid, and it smells like burning rubber when I changed it...

 

I have had the rubber exhaust hangers smell like they were burning but never caught on fire.

You have a rubber hanger on a metal rod welded to the exhaust the metal rod gets almost as hot as the exhaust so of course it gets hot!!

I have had some that worked closer to the exhaust system smell like that now knowing what it is I don`t pay attention so much.



Another thing is if your running low tire pressure it does not take long till they smell hot

It is a smell that should get your attention.

 

I think you're onto something with the exhaust hangers. I have a slight misfire and that would be making the exhaust hotter than usual now that I think about it. I'm waiting on a set of injectors to fix it. Hopefully that will have it running cooler and the smell will go away. If not I'll have to grab one of those red high temp silicone hangers like I run on my Supra.

New Tripoli, PA? I'm from Tamaqua, just up from you. If you ever see a flat tan 4Runner around, that's me.

Thanks for all the other suggestions too everyone, I ruled those all out. New coolant, auto trans, not an oil leak smell (I'm familiar with that smell, too familiar maybe).