1998 Chevy Blazer

Engine Cooling problem
1998 Chevy Blazer Two Wheel Drive Automatic

125,000 miles. My problem is car keeps over heating, the heads have been changed 2 x's and all the hoses. And water pump have been changed. Car still over heats. I do not know alot about cars. My mechanic keeps fixing the car and the 2nd time he replaced the heads, he did not charge me. We bring the car home and the next time we drive it for a few miles it over heats. The raditor starts to boil and the first time the heads wear changed it over heated and started to smoke. Now the heads are changed again. No smoke just the overheating ( the hood becomes very hot) with the raditor boils. We just keep putting water in it.
anyidea what we can do.