2011 ImpalaThe primary issue for several weeks has to do with a taping or clunking sound coming from in or under the dash when using the climate control to redirect the air flow in the car. It sometimes happens right away when I get in the car. It will usually stop 2 or 4 minutes later. Getting to the the place where I want the air to come from is taking longer and longer to get there after dialing a selection (Defrost, floor, etc). The sound sometimes is really loud or softer. Sometimes it would go on when I pushed the button to engage the air conditioning. Even after it engaged the A/C, it would take a long time for the air to start blowing through the vents and for it to be cool.




Today for the first time the water temperature went into the red. I stopped and moments later it was at the normal range. Cold air was coming through the vents when this happened. It did this twice during an 11 mile trip.

Suggestions?

 

I just went out for an 8 mile drive. The water temp needle stayed in the middle, but vent air was cool to a slight warmth with the temp selector all the way in the hot.

 

You have a blend door issue. With the sound it is making, I'd say it is broken off the hinges, or possibly an obstruction not letting it move as it should.

 

Thank you all for your support. Problems solved:

1. I had no idea "blend door" actuators were so prone to failure on Impalas. Two of the three had broken gears inside, causing the noise. I decided to replace all three of them, just in case.

2. Overheating was caused by a faulty thermostat.