Installation Procedure

CAUTION: Check the gap of all new and reconditioned spark plugs before installation. The pre-set gaps may have changed during handling. Use a round feeler gage to ensure an accurate check. Installing the spark plugs with the wrong gap can cause poor engine performance and may even damage the engine.

Gap the spark plugs to the specifications. Refer to Ignition System Specifications .

Fig 1: Identifying Spark Plug & Wire

Courtesy of GENERAL MOTORS CORP.

CAUTION: Be sure plug threads smoothly into cylinder head and is fully seated. Use a thread chaser if necessary to clean threads in cylinder head. Cross-threading or failing to fully seat spark plug can cause overheating of plug, exhaust blow-by, or thread damage. Follow the recommended torque specifications carefully. Over or under-tightening can also cause severe damage to engine or spark plug.

CAUTION: Refer to Component Fastener Tightening Caution .

NOTE: ONLY when the cylinder head is replaced with a NEW cylinder head, the FIRST time the spark plugs are installed, tighten the spark plugs to 20 N.m (15 lb ft). All subsequent tightening of the spark plugs, tighten to 15 N.m (11 lb ft).

Install the spark plugs to the cylinder head.
Tighten: Tighten the spark plugs to 15 N.m (11 lb ft).
Install the spark plug wires to the spark plugs. Refer to Spark Plug Wire Replacement .