1989 Honda Civic Smoke

Hi there,
Im afraid the problem may be more complex. Heavy smoke is usually indicative of worn valve seals. The valve seals are rubber O-rings that sit on the valve stem. They prevent oil from seeping down into the combustion chamber. When they are worn or broken, the oil drips down and burns creating the heavy smoke your are seeing. An experienced mechanic can replace the seals without removing the head. As far as the overheating, a number of things can be attributed. Since you have changed the thermostat, ensure the electric fan (if it has one) is working. Then, flush the radiator (it may be clogged). You can pick up a flush kit for about $10 bucks at any auto parts store. I hope this helps. Larry