GM S10/S15/Sonoma Pick-Ups 1982-1993 Repair Manual

Knocking Pistons and Rings


When the pistons and/rings are constantly making noise, check for the following, as necessary:

Misaligned connecting rods.
Out-of-round or tapered cylinder bore.
Loose or tight ring side clearance.
Build-up of carbon on the piston(s).
Piston-to-cylinder bore clearance is excessive.
Broken piston rings.
Loose or seized piston pin(s).