I HAVE THE 2002 SUBURBAN WITH 5.3L MOTOR AND I HAVE BEEN TOLD BY MECHANIC EITHER GET A NEW MOTOR OR A USED MOTOR..THE VALVES ARE MAKING NOISE. THE MOTOR IS KINDA QUIET BUT ONES IT GET TO 190 DEGREES THE VALVES START MAKING NOISE .IS BAD WHEN YOU ARE IN A DRIVE THRU..OH YEAH IT ALSO MAKES A KNOCKING NOISE WHEN I FIRST START IT. TIMES ARE HARD AND TO GET A NEW MOTOR OR REPLACE CAN'T DO IT..WHATEVER HAPPENED TO CHEVY'S GOOD MOTORS LIKE THE 327 OR THE 350. I HAD OLDER CARS WITH TONS OF MILES AND NEVER HAD A PROBLEMS BUT CHEVY'S 5.3L MOTORS ARE NOT AS GOOD. I BELIEVE CHEVY QUALITY ON MOTORS HAS GONE DOWN.NOW I HAVE A VERY CLEAN SUBURBAN IN AND OUT WITH BAD VALVES. ANY IDEAS HOW TO FIX IT CHEAP??

Originally thought this was the infamous piston slap on the Vortec series engines. Piston slap only occurred during cold startup. The newly discovered noise starts at 1800 rpm and continues up as far as I dare take the engine. The noise is also progressively getting louder. I removed and checked the rocker arms and push rods and found nothing abnormal. Unlike previous generation Chevy V8 engines, you cannot remove the lifters unless you pull the heads. The Suburban is in the shop for diagnostic. Mechanic verified that the noise was not coming from a piston and thought is might be coming from a roller lifter. Based on the location of the noise and cost of tearing down the engine, the mechanic recommends engine replacement. Looks like I will be doing the fixing. The shop said they have never pulled the heads on a 5.3L vortec because they are so reliable. This doesn't matter to me because my 71,500 mile Suburban needs major engine work.

Update from Jun 5, 2009: Pulled the head on passenger side and found that the number 6 cylinder exhaust valve camshaft lobe was severly damaged. This condition also damaged the roller lifter. No other camshaft lobes appear to have damage.