Geoff407

the A?C works well at start, and drive up to about an hour, on longer interstate drives it does not blow as cold as it should.. what can cause this ? my car is a 2008 C300 Sport, with under 95000 miles, in excellent condition

Plutoe

Sounds like you are low on refrigerant---while running, put a set of gauges on the system and you will know in one minute!!

JimPap

I've got the exact same car with more or less the same problem. Mine will blow cold as it should and at some point (don't think its as long as an hour) it isn't as cold. While driving, I can turn it off and then back on again and its cold.

Did you ever find out if it was the freon or something else?