Autolite APP25 Spark Plug

Autolite APP25 Double Platinum Spark Plug

Autolite APP25 is a Double Platinum spark plug built for stable ignition performance and long service life in a wide range of domestic applications. It uses platinum on both the center and ground electrodes for platinum-to-platinum firing, helping maintain consistent spark quality over time.

Compatible With many Chevrolet, Ford, and GMC trucks, vans, and SUVs, this Autolite Double Platinum Spark Plug is an OE-style replacement for vehicles that call for a 14 mm tapered-seat plug with a 0.044 in. pre-gap.

Key Features

• Double platinum firing surfaces for durable spark delivery
• Pre-gapped at 0.044 in. / 1.10 mm
• 14 mm thread diameter with tapered seat design
• 5/8 in. hex size for standard service tools
• Resistor plug with 4,000 ohm resistance
• Ceramic insulator with mid-projection design
• Platinum center and ground electrode tip materials

Product Details

The APP25 is engineered as a direct-fit ignition service part for applications that specify a tapered-seat, mid-projection spark plug. Its platinum-to-platinum electrode design helps maintain firing consistency, while the resistor construction supports cleaner ignition operation in electronically controlled systems. This part cross-references AMS Automotive 7018 for the same application.

Part number APP25 is commonly searched for fitment on Chevrolet G30, Ford F-350, and GMC Safari applications, along with many other light-duty trucks and vans from the 1970s through the 1990s. If you are replacing worn plugs on a Chevrolet Astro, Ford Bronco, or GMC Sonoma, APP25 provides an OE-form replacement format with the listed dimensions and gap.

What It Helps Address

• Hard starting caused by worn spark plug electrodes
• Rough idle from inconsistent ignition firing
• Reduced throttle response from degraded spark quality
• Fuel economy loss related to inefficient combustion
• Service intervals shortened by standard copper plug wear

Installation Notes

• Verify vehicle-specific spark plug gap before installation; some listed applications require a different gap than the plug’s pre-gap.
• Confirm thread diameter, reach, seat type, and hex size match the original specification.
• Use the vehicle service manual for torque and gap verification.
• Check ignition wires, coils, and distributor components during spark plug service.

Quality Assurance

Autolite supplies ignition products to the automotive aftermarket and original equipment channels, and the Double Platinum Spark Plug line is positioned as an OE-style replacement option for foreign and domestic vehicles. APP25 is built to match the listed form, fit, and function requirements for the applications shown.