Question:I have a 2001 Chevrolet Tahoe with a 5.3-liter engine ... But you do state it was a hydraulic (hydraulic valve lifter) noise, which typically describes a "tick," not a knock.

Earlier 5.3-liter and 6.2-liter engines were the subject of lawsuits over excessive oil consumption, lifter failure, and timing issues—many related to cylinder deactivation technology.