Autolite 646 Spark Plug

Autolite 646 Copper Resistor Spark Plug

Autolite 646 is a copper resistor spark plug built for OE-style ignition performance, quick starts, smooth acceleration, and consistent fuel economy. With a 0.050 pre-gap, stud terminal, and flat seat design, it supports a wide range of Chrysler, Dodge, Plymouth, Pontiac, Buick, Oldsmobile, Cadillac, and related applications.

The Copper Resistor Spark Plug line focuses on OE form, fit, and function for foreign and domestic vehicles. For drivers servicing older Chrysler Town & Country, Dodge Caravan, or Cadillac Fleetwood applications, Autolite 646 provides a straightforward replacement option with the dimensions and construction expected in factory-style ignition systems.

Key Features

• Copper center electrode core for reliable ignition response
• Resistor design helps reduce electrical noise in the ignition system
• Nickel center and ground electrode tip materials
• Tapered ground electrode tip design for stable spark delivery
• Mid-projection ceramic insulator
• Flat seat, 14.0 mm thread diameter, and 0.750 in. reach
• Pre-gapped to 0.050 in. / 1.30 mm
• 13/16 in. hex size with stud terminal connection

Detailed Description

Autolite 646 is an OE-style copper resistor spark plug engineered for dependable ignition service in a broad range of older vehicles. The standard/regular center electrode design, nickel tip materials, and ceramic insulator support consistent spark transfer, while the resistor configuration helps maintain clean electrical operation. This part number is commonly searched for Chrysler Intrepid, Dodge Caravan, and Cadillac DeVille spark plug replacement needs, as well as other OE-style applications across the listed fitment range. Autolite 646 cross-references Champion Spark Plug 31 for the same application.

Use Autolite 646 when you need a direct-style spark plug replacement that matches factory dimensions and gap requirements. The part number 646 is also associated with long-tail searches such as 1990-1995 Dodge Grand Caravan spark plug, 1993-1996 Chrysler Concorde spark plug, and 1975-1979 Cadillac Fleetwood OE style spark plug.

What It Helps Address

• Hard starting caused by worn or fouled spark plugs
• Rough idle from inconsistent spark delivery
• Reduced throttle response during acceleration
• Ignition noise concerns in resistor-equipped systems
• Maintenance replacement for OE-style spark plug service intervals

Installation Notes and Tips

Verify the vehicle’s required gap and confirm the listed fitment before installation. Autolite 646 is pre-gapped to 0.050 in. / 1.30 mm, but spark plug gap should always be checked against the engine specification. Confirm the flat seat, 14.0 mm thread diameter, 0.750 in. reach, and stud terminal match the original plug before service. This part fits 1995-2000 Chrysler Town & Country, 1996-2000 Dodge Grand Caravan, and 1980-1984 Cadillac Fleetwood, among other listed applications.

Quality Assurance

Autolite supplies ignition products to the automotive aftermarket and original equipment manufacturers, with a product line focused on OE form, fit, and function. Part number 646 is built to the listed specifications for direct replacement use in confirmed applications.