One day i get in my truck lunchtime only to smell an acrid smell...smelled like differential oil with posi fluid to me. Really strong. Go through whole truck, check tranny,differential...u name it. No leaks anywhere. Finally bring to toyota.they say...it smells like cat piss. Interesting i say....dont have a cat,never did,never had one in the truck. Oh...they say. We can try an a/c refresher kit..killsmold etc. In system. Ok,...now the car smelled like cheap bathroom spray...for days. Finally wearing off. The smell is coming back. The heat and a/c seem to work fine. Toyota says its an organic smell and the next step is pull the dash for 1000 bucks.i dont think so! My 200k mile 4runner runs great....but that smell, i dont think i can tolerate long term. Anyone have a clue what to do?

I assume you tried the cabin filter. I would go get the interior detailed.

Sound's like they did the treatment for mold that starts in the condenser when you don't run it long enough to dry it out. Does that sound about right?

Does the smell get stronger when you run the air? Start vehicle without anything turned on, then blast it on real quick, stronger smell? You know your vehicle better then we do, the smell likely is coming from a leak somewhere or moisture creating mold.

Any leaks in the roof? Wet carpet? Door seals?

^This ^ when I 1st joined some guys talked about this & was the condenser , some sort of thread about a fix or tsb ! Goggle search it . If I remember sounded pretty easy , like turning heater on & running stuff thru vent idk f-n old !

My Lexus started smelling like spoiled milk abruptly. So I did the research and there were a couple options for curing the smell. One was a kit Toyota brand's in a 2-pack from the dealership an the other was making sure you get the condenser hot and dried out.

I have a great sense of smell so I caught mine early enough to just get it hot and work it out. I think it pertains to a decent amount of Toyota/Lexus models, so Google should make things easy.

I keep one of those gel air refreshers in the back area. Keeps the car from smelling 12 years old on the inside.

Could it be some small rodent that decided to crawl in and die? I dunno. I have no useful advise... but my truck, not my 4Runner, got sprayed by a skunk and OMG the smell inside sucks so bad. It's like some of it is trapped in my HVAC.

It's been 2 weeks and its still lingering, even after a car wash.

So... I feel for you OP. Hope you find it.

Mice and rats LOVE our 4runners.
They can get into the cabin through the fresh air intake, behind the glovebox.

Thanks guys. No leaks....not dead mice smell...i know what that is like...i think the fan on increases it. I will try running the heater and see if it burns it off then clean the upholstry. I will keep u posted.

i would think your heater core is leaking coolant fluid thus circulating in the cabin.

ive had that on my other car. i ended up replacing the heater core. you will have to remove the dash.

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did you fix this yet?


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This! ^^^ During it's first winter here in '06, my old 4R Sport had it's silver firewall insulation chewed to hell for bedding by field mice. Yet there was no such activity on my similarly parked F-150. WTH?

My neighbors have a similar aged SR5. Not only did the damn mice do that, but they stole their dogs' and chickens' food, climbed into their 4R through the venting, and stuffed food into their ceiling liner over the entire winter - while they still used it. It was like a friggin' bean bag chair!

Bags of mint tucked behind the seats on the floorboards and mint essential oils sprayed into the engine compartments are now on my annual Fall to-do lists.

This thread and my experience as recounted in it may be helpful. Hope you figure it out!