He mustn't have looked in a 2zz head before, it doesn't have lifters. The sound is normal, nothing to worry about. 6 month intervals are the recommended time frame if you haven't reached 10,000km anyway. Umm... i think your the one who hasn't looked in a 2zz head, they have hydraulic lifters. Going in on monday, its a sticking lifter Mate watch yourself. Considering SuperDave has rebuilt a 2ZZ from scratch and put new cams in his 2ZZ head i'm pretty sure he knows whats going on with the 2ZZ. ALL 2ZZ'S MAKE THE DIESEL SOUND. STOP WASTING EVERYONES TIME WHEN YOU HAVE BEEN TOLD THERE IS NOTHING WRONG!!!!!!! hope you have fun wasting your money on monday fixing something that some mechanic has told you is wrong that doesnt exist :P i wonder what he's going to tell you he did once he takes the rocker cover off and realises its not a 1zz corolla like hes fixed before and it doesn't have hydralic lifers :P