ENGINE TICKING ON STARTUP, LASTS FOR 5 MINUTES CURRENTLY - LONGER ON COLD STARTS OR AFTER LETTING THE CAR SIT OVERNIGHT. PROGRESSIVELY HAS GOTTEN LOUDER AND LONGER IN DURATION SINCE REPORTING THE FAILURE LAST YEAR TO THE DEALERSHIP. THIS PISTON "SLAP" NOISE DESCRIBED APPEARS TO BE MANUFACTURER DEFECT IN 5.3 LITER ENGINE WHERE SHIPMENT OF ENGINES WITH CYLINDER HEADS THAT ARE OVERSIZED OR PISTONS SHIPPING AS UNDERSIZED IS CAUSING WARPING ON PISTON HEAD, HENCE THE REASON WHY THE NOISE PROGRESSIVLY GETS LOUDER AND LONGER LASTING AS TIME PROGRESSES. ORIGINAL DEALERSHIP HAS DOCUMENTED THE REPORT OF THE NOISE WITH NO RESULT OR ATTEMPT TO FIX. CUSTOMER HAS PURCHASED EXTENDED WARRANTY PRIOR TO THE EVIDENCE OF THIS FAILURE, AT TIME OF PURCHASE. SEVERAL DEALERSHIPS HAVE DIRECTED CUSTOMER TO FILE A DIRECT COMPLAINT WITH MANUFACTURER AS ENGINE HAS BEEN DIAGNOSED THAT PROLONGED WEAR WITH THE "SLAP" THAT IS CAUSING THE TICKING NOISE WILL CAUSE SERIOUS DAMAGE TO ENGINE OVER TIME. ONLY SUGGESTED RECOURSE IS TO REPLACE ENGINE WITH 5.3 THAT SHIPPED AFTER SEPTEMBER 2002 AND WAS NOT MANUFACTURED FROM ONE OF THREE GM PLANTS RESPONSIBLE FOR THE MANUFACTURE OF THE DEFECTIVE ENGINES.