I have an 06 MCS and the tire pressure warning light came on the other day. It has been getting colder here. I checked the tire pressure and all of the tires were 4 pounds lower. I double checked to make sure I read the gauge right. As a rule of thumb, ten degreees lower equals one pound drop in pressure. Anybody else had this happen?

 

Have nitrogen installed in your tires. You won't loose air pressure as fast.

 

My wife's car lost 3lbs in every wheel since I checked them 1 month ago. It happens to me regularly during the change in seasons.

I've never understood the nitrogen argument for not losing pressure so quickly... Air is 70% nitrogen anyway! It's possible that, under hard driving, the tires would warm significantly, the more water vapor in the air (vs. pure nitrogen) would expand (lots of heat to make steam... esp. under pressure) and would leak out, causing a neet decrease in pressure once the tires cooled.

I'm not saying that Nitrogen doesn't help... I'm just saying that I don't get it.