I have a 97 mercury mystique with 130000 miles on it. I went to a mechanic in february with what I thought was an exhaust problem. They informed me that I had time belt issue, so the changed the timing belt, waterpump, thermostat and thermostat gasket. I still had a loud exhaust sounding noise coming from my car but two to three weeks later, I was gasing up and my car stalled out. I took it back to the same mechanic who informed me it was a MAF that needed to be cleaned, I was again picked it up and it stalled out before I got off the lot. The third time they replaced the iac valve for me. Well the exhaust sound never went away so I took it to another mechanic who is certified. At this time he informed me that my waterpump was leaking and the idling in my car was due to the timing belt needing to be retimed and to take it back to the mechanic because of the warranty. I did so the first mechanic said nothing was wrong with the water pump and the timing was fine that there was a misfire. So I got a tune up and a month later my car overheats and now is dead. A third mechanic informed me it was a waterpump problem and there was coolant in the engine to take it back to the first mechanic. The first mechanic said that the head gasket is blown and they are not responsible for it and will not take a further look to see if it was cause by the waterpump because that would require taking the engine apart. My questions are how can you tell a head gasket is busted without taqking the engine apart? If the head gasket would not have been broken if they had fixed the leaking waterpump? What would be my next step?