I have a 1997 Subaru Legacy L 2.2 Liter with 288,000 miles. A home mechanic did the timing belt (best OEM kit I could find for $196 with pulleys, tensioner, water pump and belt). He said I should do the thermostat (he said he put in a cheap $10 thermostat) and all new coolant so timing belt job and new thermostat and coolant all at once in April.
Immediately, right after that job, first time in 12 yrs driving my car, there was a major sloshing sound in the dash like air in the coolant line. The mechanic said don't worry it will eventually go away. It never did yet only went on short errand type trips up until my first long trip in September 80 miles out my temp gauge went to major overheat. I put in 1 quart of fluid. A mechanic on the road did the purple dye test and said no head gasket leak but that his testing took out a lot of the trapped air. Sloshing was far less. He said watch the level and keep adding until it goes away. I drove 80 miles home no problem, and added some fluid and did short trips okay for a while. Then suddenly on a short trip it took me 1 1/2 hrs to slowly get home again with constant over heating. It took it to a pro shop and mechanic said the cheap thermostat was working fine yet that he saw a bubble every 30 seconds in the coolant fluid. He then concluded it's a blown head gasket and to junk the car. I asked if it could be the trapped air from the sloshing still under the dash and he said no junk the car. Should I get a second opinion? I don't see the steamy exhaust, it idles very nice and starts very well, it still sloshes and I've been on several errands and all okay. I have very good acceleration... What should I do?