A few weeks ago I noticed that when I drive with my windows down and come to a stop, occasionally I get a whiff of antifreeze. I've checked for leaks on multiple occasions and I havent found 1 drop. Theres also a slight smell after driving toward the engine bay but when the engine begins to cool the smell goes away.
I'm pretty sure I'm not losing any coolant but if I am I'm losing it slow enough that I can't tell with checking every few days.
Anyone know what I should check?

Btw its a 01 4runner 3.4 auto with 90k

 

Heater core maybe...passenger side floorboard wet under the dash?

 

Very small leak around the water pump gasket or even a pin hole in the pump? Is it full? Maybe low and heating up a bit. Mike

 

At 90k, I'm also betting on the water pump. Mine went at 75k.

Also, check the radiator. Do you see any residue on top or the bottom of the radiator?

 

Pass floor board is dry, radiators full an overflow is where it should be, and if there's a leak around the water pump I cant see it.

 

When was the last time you gave it a good flush and new antifreeze? Can't hurt to do that. Mike

 

keep checking your levels. it could be a small leak. make sure your caps are tight also. take the black cover off and look closely at the water pump and the thermostat for any sign of leakage.. just bc it isnt hitting the ground doesnt mean its not leaking. at 90k i am thinking thermo, pump or leak. not the heater coils.. if you havent flushed then do that.

 

Check the weep hole at the bottom of the water Pump. Wipe your finger on the bottom of the WP or use a small mechanics mirror and see if you see any residue/AF/signs that it is leaking. Many a time i have seen where there is no visible fluid but check the weep hole and it has the signs that it is starting to go.

 

leak at one of the heater hoses that drips down the back of the motor and evaporates before it ever leaves a puddle....

the reason you smell it is because it has evaporated and you can then sifff the vapor....