mystery aroma and it's kinda nasty.

[Blanco]

I have searched on this subject and although many 4Runner owners have complained about similar smells, I haven't really found any solid answers. It was hard enough to convince my wife that removing the running boards was a good idea but this smell ain't gonna cut it with her and it's our daily driver...haha!

Here's the deal, a couple of days ago my Runner randomly started giving off a sort of hot rubbery, plasticky, almost fishy smell emanating from the passenger side. Kind of reminds me of what you smell after you spray that 'No Touch' style of tire cleaner onto your tires and it starts cleaning - nasty. I first noticed it when I rolled down the passenger window.

It only seems to smell when I'm moving (this could be because the smell is being blown into the cabin when mobile) and it's not coming through the HVAC system. When I'm stopped, I cannot smell anything under the hood, around the brakes or the exhaust. The smell stays in the truck after I'm stopped though.

I speculated that it might have been a small oil leak hitting the exhaust manifold, but it's not really a hot oil smell per se and I couldn't really see any leaking around the valves. I also checked my rear heater lines (which are corroded) leaking onto my exhaust but nothing I could see. Took a look at my brakes but they seem to not be overly hot on any one particular wheel and no abnormal brake dust buildup and it doesn't really smell like overheated brakes.

I've got to say, I'm pretty stumped on this one, but if I had to guess, I'd say coolant as that can have a kind of rubbery, fishy smell but don't see any obvious leaking anywhere.

Anyone else experience this and find out the source?

Thanks.

 

[t4r4life]

get a pump insert into rad pumo to 15psi and watch for drips and trace it back if its coolant

 

[ALBPM]

Sounds like a leak in the heater core which is on the passenger side under the glove box. Is the carpet getting damp under the glove box??

 

[theizzardking]

people rarely check and clean the inside cabin air filter, it's probably a good 10 years old now and has never been replaced. i'd do that first then start worrying about things being broken and mystery leaks as that may be a nightmare and $$$. i like cheap and easy first...

as with anything keep an eye on your fluids for the next few weeks and see if there is any loss, if so then you know which lines to start chasing down for leaks.

 

[Blanco]

Thanks guys. I thought about the cabin filter and heater core and such but I can really only smell it when the passenger window is down and I'm moving.

Closed all the windows and cranked the vents through, fresh air, A/C and then heat but no odor.

Will keep an eye on fluids and look for any drips. Hopefully the smell will just go away!

 

[J-money$$$]

people rarely check and clean the inside cabin air filter, it's probably a good 10 years old now and has never been replaced. i'd do that first then start worrying about things being broken and mystery leaks as that may be a nightmare and $$$. i like cheap and easy first...

as with anything keep an eye on your fluids for the next few weeks and see if there is any loss, if so then you know which lines to start chasing down for leaks.

THere is not a cabin filter on these trucks. At least there isnt one on my 97. maybe later versions have one

 

[IanB]

THere is not a cabin filter on these trucks. At least there isnt one on my 97. maybe later versions have one

I was going to say the same thing, I was unaware we had cabin air filters in these trucks.

 

[Nervo19]

No cabin air filter in my 2000. I think they began with the 5th gens.

 

[JohnsD90]

Does it only smell when your wife is in the car? if so...

 

[t4r4life]

Does it only smell when your wife is in the car? if so...

dude! not cool!

 

[Baja Runner]

First thing to come to mind is leaking axle seal, and the diff fluid burning while braking. This will happen in the rear axle. Check the rear of the drums and see if they are saturated with oil.

DO you smell it when you get out of the vehicle, after driving?

 

[pdx650]

THere is not a cabin filter on these trucks. At least there isnt one on my 97. maybe later versions have one

Maybe it's time somebody tried to mod one for these 3rd genners...to include my '97. I'll look into it and see what I can do...after I get my ride back from the autobody shop.

I got my ride back from the autobody and we're good now.

 

[1985taylor1925]

This sounds like the same thing I started a thread about a few weeks ago! The advice I was given was that it was probably an oil leak burning off on the manifold. But Im fairly certain thats not it. I only smell mine after driving at 60 or over for a while, and then coming to a stop. The smell comes as I am slowing down and stopped, lingers for a bit, then goes away. So for me it seems associated with higher speeds. Though I never smell it driving at highway speeds, only when coming to a stop. And it is a wierd combo of like burning rubber/plastic/electronics all together. Its not oil. The first time I smelled it was right after I had my transmission fluid changed back in august, so I wondered it there was a break in period where tranny fluid gave off a smell. However Ive checked the tranny fluid and no smell. Also since it started I havent lost any coolant, so this is really a mystery to me.

 

[BrianSD_42]

THere is not a cabin filter on these trucks. At least there isnt one on my 97. maybe later versions have one

Thanks, after read the first few post I was thinking --- I guess I should look into changing my cabin air filter since I have never changed it.

 

[Blanco]

This sounds like the same thing I started a thread about a few weeks ago! The advice I was given was that it was probably an oil leak burning off on the manifold. But Im fairly certain thats not it. I only smell mine after driving at 60 or over for a while, and then coming to a stop. The smell comes as I am slowing down and stopped, lingers for a bit, then goes away. So for me it seems associated with higher speeds. Though I never smell it driving at highway speeds, only when coming to a stop. And it is a wierd combo of like burning rubber/plastic/electronics all together. Its not oil. The first time I smelled it was right after I had my transmission fluid changed back in august, so I wondered it there was a break in period where tranny fluid gave off a smell. However Ive checked the tranny fluid and no smell. Also since it started I havent lost any coolant, so this is really a mystery to me.

The smell comes and goes for me now but still rears its ugly head every now and then, at various road speeds. I'm thinking its gotta be coolant hitting something hot, then burning off - just wish it would give off the smell once I've stopped so I could locate it. Has anyone experienced any coolant leaking from valve cover gasket onto the manifold or exhaust? Where might be the hotspots to inspect for potential leaking? I can't see anything really.

 

[SR54Runner01]

First thing to come to mind is leaking axle seal, and the diff fluid burning while braking. This will happen in the rear axle. Check the rear of the drums and see if they are saturated with oil.

DO you smell it when you get out of the vehicle, after driving?

I had a leaky differential seal spraying all over the interior for a number of months, ultimately dripping off the engine onto the garage floor. Problem fixed, but to this day I get a nice whiff of burned synthetic lube coming out of the HVAC when I start the car up.

 

[lekiboy]

it is the heater core under the passenger seat- you can put your nose there and smell the core just under the seat...

am living in asia and i do not need it..if you also don't need the heater and have no time repairing the leak- remove the fuse under the dashboard - left side...the fuse cover has the diagram to know here the heater fuse is located.

am very sure this is the heater core- sweet smelling almost like from the sewers.. - try this first before doing more complicated things.

 

[jacktahoe]

No cabin filter on my 98, but my 2004 has one.

 

[pcarenthuz]

I've experienced what I believe is the same odor/aroma as being described here. In my case though it's definitely not antifreeze/coolant -that is distinct and sweet perfume-like. I'm pretty sure mine is related to the temperature control circuitry (printed circuit boards) not working correctly. I've only had my rig for one month and few of the button selections work reliably. In fact, I can no longer get the A/C to turn on. When all of this was more intermittent (A/C, reverse air, windshield defrost worked occassionally), I would notice a burnt, plasticy odor as described here.

In any case, I'm pretty sure I need to diassemble my cabin air control module and replace the board(s) if they are available.

Pat Arnold