With the change in weather I noticed a few changes with my car.

PA had recent snow and ice. I started my car and heard this loud rumbling like a cat may have been underneath my car. Opened the hood and found ice chunks. I did remove as much as I could but it was frozen around the hoses as well. After about an hour of driving the knocking went away. ALL IS WELL- Just wanted to let you guys know in case you come across the same thing.

THE PROBLEM~ I had my defrost on and had it on the circulate. I turned the defrost off and moved the "speed button- the 0-4" to 0 so it would be off. I can still hear the defrost running and can feel air out of the vent up top by the windshield. I never noticed this before and I think it may be a problem. Can anyone help with this?

 

That is normal. Every car does that. Whenever you have the air to shoot up the windshield the car automatically switches to let the air from outside in. Even if you push the button to have the air recirculate, it will not let you. Since the vent is open to let the outside air in, even though the fan speed may be at 0, some air will still come in and the faster you drive or if you have a window open the more air will come in. If you don't want air to come in anymore you just have to switch the mode and press the circulation button so that the orange light shows.

 

when you turn the dail to defrost, you will hear a vent closing. thats because the vent to recirculate closes and the vent to let inside air come in opens.

and btw, whats the best way to heat my car?? recirculate or use outside air??

 

Recirculate is the best way to heat or cool your car

Ex: Outside air - 90F, In-vehicle temp 80F - Desired temp- 70 F

On fresh air mode, the system would have to achieve a 20 degree change in air temp, whereas on recirculate it only needs to achieve a 10 degree change. Same thing goes for heating.

It's a lot easier to heat 50 degree air to 70 than it is to heat 20 or 30 degree air.

It's all about temperature differential.