Just an hour ago I reopened the air box to make a more permanent and neater plug on the pre-heater hole/flap. This was the third freaking time I loosened the AMM from the body mount, loosened the two clamps on the U-shaped pipe, and removed the now beaten but still in good shape filter. My back was still sore from the bending over and stretching from the two previous tasks, but I was determined to give myself a piece of mind and just that I can be so obsessive and freaking anal about things. I had tape ready and was going to remove the strips of duct tape that I had unprofessionally slap over the flap this morning. This job was going to be a much neater and permanent fix so that the flap won't untape itself and open up. I carefully removed the old tape and guess what? The flap was tightly closed with the tape removed. The thermo does work after all. Here is my take on it, and I guess it's about time I contribute something useful to the board, as I am usually always asking questions :o)

The first task of opening the air box to change the filter. The car had been driven earlier on a 20+ mile trip, but I let it sit and cool for a good 3 hours. The weather outside was cloudy but otherwise a comfortable 70 something F. when I got set to change the filter. The engine was cool but not stone cold. Air flap was open even though it is supposed to close at around 60F.

The second task of opening the air box to check on the condition and status of the air box thermo. The car had been sitting the whole night. The weather outside was sunny and the temperature was somewhere in the mid to high 70s when I decided to look into the air box. The engine was stone cold from sitting all night. Air flap was open. I did a blow-dryer test, but did not see the flap go down. I don't think I held the dryer there long enough for the thermo to act. Also, someone said that the flap closes very slowly. So my impatience gave me a wrong diagnosis. I taped the flap shut thinking that I had a bad thermo.

The third--and final--task of opening the air box to permanently tape the pre-heater hole shut. The car had been driven (aprox. 14 miles) and had only sat for less than 30 minutes when I decided to reopen the air box. The sun was setting and the temperature was around high 70s to low 80s and the engine was still hot when I looked at the flap. It was closed shut when I removed the tape. I studied the air box and stuff. My reasoning for why the air flap was open the first two times is that the engine/engine compartment was not in operating (or near operating) temperature. The third time it was closed because the engine/engine compartment was in operating or near operating temperature. I also remember reading that it is normal for the pre-heater flap to remain open despite outside ambient temperature over 60F when the car is "cold" or cool so that the engine can heat up faster. I guess if you decide to change your air filter and see that the flap is open despite the outside temperature to be higher than 60F, don't naturally assume the thermo is bad. It really depends whether you are changing the filter after your car has been sitting over night or whether you are changing the filter after driving the car.

I decided to not tape the pre-heater flap, as it seemed to be working. Man, my back is sore and so are my arms and legs. Thanks to the brickboard, I now know there is a thermo in the air box and that it needs to be checked. I can sleep now.