Im not familiar with the ztechs...but it sounds like a water pump. I know the Duratechs use a plastic impeller in threre water pumps witch cause them to go out early.

You may want to check to see what kind of impeller is used on the Z tech water pumps. If its plastic I reconmend changing it.....and that might solve your problem. Look in to it....I hope it helps

ROZ


3.0 SVT hybrid...all the fixens...Track/Race ready very soon!!!!!! 20,000 + miles