Autolite APP145 Spark Plug

Autolite APP145 Double Platinum Spark Plug

Autolite APP145 is a double platinum spark plug built for older GM and Pontiac applications that call for a tapered-seat plug with a 0.040 in. pre-gap. It uses platinum on both electrodes for consistent firing and long service life, while the resistor design and ceramic insulator support stable ignition performance.

Key Features

• Double platinum firing surfaces for durable spark delivery
• 0.040 in. pre-gap, 14 mm thread diameter, and 0.433 in. reach
• Tapered seat design with a 5/8 in. hex for service access
• Resistor plug with ceramic insulator and short projection design
• Compatible with a wide range of Chevrolet and GMC truck and van applications

Detailed Description

The Autolite APP145 spark plug is engineered as an OE-style replacement for a broad range of classic Chevrolet and GMC light- and heavy-duty vehicles, including Chevrolet C10, K20, and P30 applications, as well as GMC C15, K25, and Jimmy models. The platinum-to-platinum design helps maintain spark consistency over time, and the tapered ground electrode supports reliable ignition under regular driving conditions. Autolite APP145 is also referenced by cross numbers 7516 and 41-821 for the same application.

Autolite positions this Double Platinum Spark Plug line as a direct-fit alternative for foreign and domestic vehicles where OE form, fit, and function are required. For Chevrolet C10 and GMC K25 owners restoring or maintaining older ignition systems, APP145 provides the specified plug geometry and electrical characteristics needed for proper operation.

What It Is Used For

• Hard starting caused by worn or inconsistent spark plugs
• Misfire concerns related to degraded electrode surfaces
• Reduced throttle response from weak ignition output
• Fuel economy loss tied to inefficient combustion
• Service replacement on older Chevrolet and GMC ignition systems

Installation Notes and Tips

Verify the required gap and seat style before installation, since fitment notes include multiple gap specifications across applications. Confirm the vehicle’s ignition system requirements and match the plug to the listed year, make, model, and notes. Use the correct torque procedure for tapered-seat spark plugs and inspect plug wires or boots during service.

Quality Assurance

Autolite supplies ignition products to the aftermarket and original equipment manufacturers and is a long-standing spark plug supplier. APP145 is built to OE form, fit, and function standards for the listed applications.