2001 Sienna LE - Smelly A/C Problem

[jman_va]

Starting last year somepoint, my Sienna developed a rather odd A/C problem.

Whenever I turn on the A/C for the first time after the car has set for a few hours or overnight, the A/C for about 5 min smells awful. The best I can describe it as is a musty gym-sock. It does not have any sulfouros / rotten-egg smell, but more of just a sweaty, musty old gym-sock.

The smell goes away completely after opening the windows and letting the A/C run for about 5 min, but it is an eye watering / almost gaging 5 min if you leave the windows up. It is also embarrising to say the least when you have guests in your car.

It does not matter wheather the A/C is on recirculate or fresh air, the first few min are always funky, but it does always clear up. After the smell goes away and I turn off the car, if I return within an hour or so, it does not smell when turning it back on, only when left off for a few hours or more.

Ideas??? Thanks!

[clubfoot]

I had a similar experience in my IS350, I believe it's because the A/C runs continuously in the IS until 4 degrees. It took a while but leaving my car out in the sun and only using outside fresh air for a few days cleaned up the odour. There are also products you can purchase from parts stores that you can spray into the fresh air intake at the base of your windshield that may help.