Get quick starts and dependable spark with the Autolite Copper Spark Plug 646. It's cataloged for a broad list of vehicles, from the 1987-1988 Buick Skyhawk [L4-2.0L] and 1975-1976 Cadillac DeVille [V8-8.2L] to the 1993-1996 Chrysler Concorde [V6-3.3L] and 1990-2000 Dodge Caravan [V6-3.3L] — see the Buyer's Guide tab for the full application list.
This is a resistor plug (4,000-ohm resistance) with a standard center-electrode design and mid projection. It uses a 14 mm thread (M14 - 1.25, metric), a 13/16 in hex, a flat seat with the washer included, a 0.75 in (19 mm) reach, and manufacturer heat range 8. It arrives pre-gapped at 0.05 in (1.3 mm) — verify against the vehicle service information before installing. Quantity needed varies by engine (4, 6, or 8); plugs are sold individually, so order the number your engine requires. Country of origin: Mexico. Backed by a 2-year limited warranty.
Interchange: 117 · 41-618 · 41618 · R44XLS6 · R45NSX · R45XLS6 · C95R6 · 7522 · 7922 · W10EC · WR10LCV · WR10LCV+ · 31 · RN14MC5 · RN16YC5 · 4686083 · 3015 · 32721 · 25312033 · 5613932 · 5613946 · 5614128 · SP0RN14MC5 · AGR52-6 · AGR526 · AGS52C6 · AGS52C-6 · SP451 · 4012 · BP5ES-13 · BP5ES13 · GR45 · GR55 · SF6F6 · Manufacturer part number 646
This part cross-references / interchanges with the following part numbers:
What type of spark plug is the Autolite 646?
It's an Autolite copper spark plug with a copper core center electrode, high nickel alloy electrodes, and a high alumina multi-rib ceramic insulator.
Is the Autolite 646 a resistor spark plug?
Yes. It's a resistor-type plug with 4,000-ohm resistance, which helps suppress ignition-system electrical noise.
What are the thread and fitment specs?
It has a 14 mm thread (M14 - 1.25, metric), a flat seat with the washer included, a 13/16 in hex, and a 0.75 in (19 mm) reach with heat range 8.
Does it come pre-gapped?
It ships pre-gapped at 0.05 in (1.3 mm). Always confirm the correct gap against the vehicle service information before installing.
How many plugs do I need to order?
Quantity varies by engine — the listed applications use 4, 6, or 8. Plugs are sold individually, so order the number your engine requires.
WARNING: These products can expose you to chemicals including lead and phthalates, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.
