Toyota Repair: overheating toyota truck

Question
94 Toyota deluxe truck...6 cyl...3.0...automatic...all was fine then I got the timing chain done and since they were there they put in a new waterpump(authorized repair and parts)....no problems before was just trying to do things right....since then anytime you put a load on the engine(up a hilletc) it shows it's overheating and I must say when I got it back I felt it had less "balls"...5 mechnics could not duplicate the problem...no leakage at this point...replaced radiator, fan clutch, thermostat. sensor,tried blue devil additive and even replaced waterpump...now it's worse ..coolants been flushed now at least 3 times..what's left to do regarding keeping my engine from overheating? supposedly everything been checked and double check by several mechnics and to make sure correct parts are being used...they are....169,000 miles and for a Toyota that's not much...now it overheats without putting a load on it when you run with a/c for less than an hour on the freeway.oh yeah everyone says head gaskets but no leaks so no one is sure...THANKS>>>>. help!!!!!!

Answer
Hello, why don't you have a headgasket/internal combustion leak test done to see if anything shows up? You can actually do this yourself by getting a relatively inexpensive test kit from most auto part stores, just follow the instructions that come with it.