2003 Chevrolet Impala. Engine Size : 3400 Question: overheating., have changed water pump, thermostat,intake gasket, and radiator please help. Need a solution.....
Answer: Looks like you've covered just about everything there is, except the big one. Basically, the only thing left would be a blown cylinder head gasket. Have seen this many times on the 3400 engines over the years. Usually it's just the back cylinder head,
but if you have a lot of miles on the car, or cannot exactly diagnose which head gasket is leaking, you should replace both head gaskets. If you see a constant stream of bubbles in the coolant, with the car running and radiator cap removed, you know for sure that compression is getting into the cooling system via a blown head gasket. If you've done the other work yourself, doing head gaskets really isn't that much more involved. Do NOT re-use the old head bolts. You need new head bolts, and there is a special procedure for tightening them, including a final angle sequence. The exact spec is 44 ft. lbs. on a first pass, then a final pass of 95 degrees. You need a special torque angle meter to complete that procedure.
