What is Piston Slap?
Piston slap is caused when there’s too much space between the piston and the cylinder wall. The piston moves up and down in the cylinder and the extra clearance results in a greater amount of rocking in the cylinder, producing a loud knocking noise. Vehicles with the engine knock problem include 1999 – 2002 GMC and Chevy pickups and sports-utility models with 3.1, 3.4, 4.3, 4.6 (Northstar), 4.8, 5.3, 5.7(LS1), 6.0 or 8.1 liter engines. Specific models include (but may not be limited to): Chevrolet Silverado, Tahoe and Suburban, GMC Sierra, Yukon and Yukon XL. The 2002 Cadillac Escalade SUV also reportedly suffers from the problem.
