Lifter tick is a common occurrence in V-8 engines like the Chevy 5.3-liter Vortec. This ticking sound is caused by the valve lifters, which are filled with oil during engine operation. When your engine sits, the oil can seep out of the lifters. When this happens, the lifter will tick at start-up until it refills with engine oil.
Impact on the Engine
Ticking lifters are not dangerous. The lifter is designed with a drain/fill hole that allows the lifter to float or fall based on oil pressure. An old trick is to run a thicker engine oil, which remains in the lifter longer after the engine is shut off. This is not advised in newer 5.3-liter V-8s, however, which specify 5w-30 oil. Keep in mind that heavier oils are slower to lubricate when the motor is first started, particularly on a cold start, which can lead to additional wear and tear on the engine.
Running engine cleaner through the engine can help remove carbon deposits that can contribute to ticking at start-up.