strange smell

[03silverv6]

now that it is getting cold up in here in Mass. i have noticed a strange smell when i turn on the heat. this happened only twice so far. the other day and maybe two months ago. both times it was when i was running the defroster and had it at the highest power right ofter starting the car. it stays for maybe a few minutes no more than 5 minutes. it is not a burning smell or at least it doesnt smeel like it. i dont no how to describe it. it is awful causing me to shut it off for a while and then it is gone. anyone had this happen and no if it is a problem wit the car or just a freak thing. thanx

 

[chromedog]

is it a sweet smell? do the windows fog up when you run the defroster? heater core is leaking...

 

[232Mustang95]

Can also be mold

 

[03silverv6]

not really a sweet smell and the windows dont fog up when i run the defrost. i dunno if it could be mold the car is farely new. if it were mold is that a problem or nothing u can do about it. it does not happen all the time. did not happen at all today or yestarday. thanx