Just changed the thermostat
squeeky belts then heat turns off-- fan still runs, but it then over heats... on 1994 Mazda Miata MX-5
Check your radiator line feeding the engine for compression. Make sure the radiator and overflow bottle are full. If your losing compression this is bad. It should be a very tigt line to squeeze. If not you could have a leak in the radiator. It could go as far as the heater core being bad. You need to narrow it down. Check the oil stick for a milky color. That could mean a head gasket or head job. Your problem needs to be narrowed down. But if you continue to drive it no matter what the problem is you can blow the Head. Major fix...