When my car gets hot I occasionally get a whiff that I can't completely identify. I want to say that it's coolant maybe leaking from my heater core but there is no evidence of moisture and this smell has been going on for awhile and I've never added coolant - the car still runs in the proper heat range for a hypertech thermostat equipped car.
Any Ideas

 

you gotta be more specific. Is it with the A/C on, the vent on, the windows down, windows up. Maybe your overfill canister is leaking or you have small leak somewhere.

 

Windows up, windows down. AC on/off, vents on/off. Once I detect the smell does'nt seem to matter. The only correlation appears to be heat related. I do believe it is coming into the interior from someplace other than the windows. I normally drive with windows open and can't smell it once I get going, unless I close the windows, then it's still there - in other words the air circulation seems to take the smell away. I notice it more when I'm stopped at a light for instance.

 

That would lead me to believe that it is heater core related. Yet, the simple fact that you do not have any moisture deters me. In other words, I have no clue. Best bet is just to look for a leak. Look for any kinda white flaky buildup (corrosion) on all the tubes and hoses. Double and triple check under your passenger side dash area for moisture. Good Luck.