I have a 1991 Plymouth Acclaim 2.5 and the heater is not blowing hot and there is bubbles in the cooling system. The Head gasket has been in place for about 4 years and I am wondering if it had gone bad again. other symptoms are rough Idle and lowered fuel efficiency, the problem continued even after I replaced the thermostat.I have not had a chance to pressure test the cyl's yet but that is slated for this Thursday providing that I can find my tester. The Engine has Overheated a few times, and I am wondering if it is time to have my spare head rebuilt and install it. Any thoughts are welcomed.