In short: the 2018 Silverado uses iridium-tipped spark plugs, with the exact type depending on the engine: 4.3L V6, 5.3L V8, or 6.2L V8. Always verify the precise part number and gap from GM’s official specifications or the owner's manual, and opt for OEM or OEM-equivalent plugs for best results.
The Silverado lineup for 2018 offered three gasoline engines, each requiring a distinct spark plug configuration to balance longevity, performance, and reliability. This article outlines the plug type associated with each engine and how to source the correct replacement.
Engine options and spark plug types
4.3L V6
The 4.3L V6 in the 2018 Silverado uses iridium-tipped plugs designed for long life and dependable performance. Plugs are typically pre-gapped for ease of installation and ignition compatibility.
- Plug type: Iridium spark plugs; Gap: approximately 0.040 inches (pre-gapped).
Always verify the exact part number and gap in GM service information or the owner's manual, as there can be revisions between model builds.
5.3L V8
The 5.3L V8 shares the iridium-tipped design, with a pre-set gap around 0.040 inches. OEM replacements from AC Delco (and equivalents from NGK) are commonly used and supported by GM documentation.
- Plug type: Iridium spark plugs; Gap: approximately 0.040 inches (pre-gapped).
As with all engines, use the plug part number specified by GM for your build year and engine code.
6.2L V8
The 6.2L V8 in the 2018 Silverado also employs iridium-tipped plugs with a pre-set gap near 0.040 inches. When replacing, select OEM-equivalent plugs that match GM’s specifications for your VIN.
- Plug type: Iridium spark plugs; Gap: approximately 0.040 inches (pre-gapped).
Double-check the official GM documentation to confirm the exact plug number for your vehicle.
Notes on replacement and sourcing
To ensure you’re using the correct spark plugs for your specific Silverado, reference the owner's manual or GM service information for your VIN. If you prefer aftermarket options, look for iridium plugs rated for your engine and verify compatibility with the 2018 Silverado lineup.
In all cases, using OEM- or OEM-equivalent iridium plugs is the standard recommendation to maintain performance and longevity. If in doubt, consult a certified mechanic or Chevrolet dealer service department.
Summary
The 2018 Chevrolet Silverado uses iridium-tipped spark plugs across its gasoline engines, with the exact plug type and gap tailored to the engine: 4.3L V6, 5.3L V8, or 6.2L V8. Always verify the precise part number and gap from GM’s official specifications or the owner's manual, and opt for OEM or OEM-equivalent iridium plugs for best results.