I know that some people have complained of this issue, and I just thought I'd share my experience with it. At 42xxx miles, my sonic is losing coolant. It is a VERY slow leak, but a leak no the less. I can't smell any coolant, nor do I see any puddles, so I took it to the dealership yesterday so they could fix it. The dealership had the car for over six hours... all they preformed was a pressure test and concluded that there was no leak. Now, I've already added about a quarter of a gallon to the tank, so I know the coolant is going somewhere... But according to the dealership all is well. Another issue is I purchased the extended bumper to bumper warranty (dumb) but still they tried to charge me for "diagnosing" my car. When I went to go pick up my car, I asked about the charge and the employee explained that nothing was wrong, so they were charging me a half hour for the time spent working it (5 minutes...10 max.) I asked the gentleman where the coolant went, and he casually explained to me that since coolant is water based and my car had so many miles on it, it simply evaporated... Now I've been around cars my whole life. For someone to try and dupe me with some bs really pissed me off. I explained to him that the cooling system is a closed system and liquid neither leaves or enters the system. It is a pressurized system and saying that coolant can leave is counter intuitive to that fact. He stammered something else and I quickly informed him that my wife's car has 212xxx miles on it and has never lost a drop of coolant. He told me that there would be no charge for the "diagnostic" and to bring it back IF it got low... Sorry. Just needed to vent a bit and get your guys' opinion on the matter. Should I try another dealership? Should I just let it get low again and go back to the same people who tried to take me for a fool? Anyone else experience unexplained coolant loss that the dealer finally fixed or is this behavior typical for a dealership?