GM: Electra/Park Avenue/Ninety-Eight 1990-1993

Spark Plugs



To avoid engine damage, do not remove spark plugs when the engine is warm; the spark plug threads may be stripped if removed on a hot engine. When you're removing spark plugs, you should work on one at a time. Don't start by removing the plug wires all at once, because unless you number them, they may become mixed up. Take a minute before you begin and number the wires with tape. The best location for numbering is near where the wires come out of the cap.

  1. Disconnect the negative battery cable.
  3. Use a small prying tool to remove the heat shields on the rear cylinders.
  5. Remove the first spark plug cable by twisting the boot half a turn, then pulling up. Then remove the spark plug.
  7. All engines used AC Type R45lts6 spark plugs until an updated non-ridged spark plug was introduced in February, 1992, designated 41-600 (this number may change at any time). Properly gap to 0.060 inch (1.5mm) prior to installation.
  9. Lubricate the threads lightly with penetrating oil and install the spark plug. Torque to 20 ft. lbs. (27 Nm) for 1990-91 engines and 12 ft. lbs. (16 Nm) for 1992-93 engines. Install the cable to the plug and snap it in place.
  11. When installing the heat shields, make sure they are seated against the bump stop and the lower tabs extend over the spark plug's hex.
  13. Repeat for the remaining spark plugs.
  15. Connect the negative battery cable.