Denso 5033 Spark Plug

Denso 5033 U-Groove Spark Plug Overview

The Denso 5033 is a conventional spark plug built for steady ignition performance in a wide range of Ford, Mercury, and Mazda applications. Its U-Groove ground electrode design helps improve ignitability, supporting more efficient combustion and consistent engine operation.

As part of Denso’s U-Groove Conventional line, this spark plug combines a copper core center electrode with nickel tip materials and a standard ground configuration for dependable secondary ignition service. The tapered seat, 14.00 mm thread diameter, 18.00 mm reach, and 16.0 mm hex size make it a direct-fit style plug for the listed applications.

Key Features

• Part number: 5033
• U-Groove ground electrode design for improved ignitability
• Conventional spark plug construction for everyday engine service
• Copper core center electrode for stable spark delivery
• Nickel center and ground electrode tip materials
• 5000 ohm resistance
• Pre-gapped to 1.5 mm
• Tapered seat design
• 14.00 mm thread diameter and 18.00 mm reach
• 16.0 mm hex size

U-Groove Conventional Line Details

Denso’s U-Groove Conventional spark plug line focuses on ignition efficiency through the U-shaped ground electrode profile. That design helps expose the spark kernel more effectively, which supports cleaner combustion behavior in engines that call for this plug specification. The Denso 5033 follows that approach while using conventional materials suited to routine replacement service.

Vehicle Fitment

• Fits 2009-2011 Ford Ranger, N/A
• Fits 2006-2010 Ford Explorer, N/A
• Fits 2007-2010 Ford Explorer Sport Trac, N/A
• Fits 2006-2010 Ford Mustang, N/A
• Fits 2007-2010 Mercury Mountaineer, N/A
• Fits 1994-1996 Mazda B4000, N/A
• Fits 1991-1994 Mazda Navajo, N/A
• Fits 1986-1990 Ford Escort, N/A
• Fits 1986-1987 Mercury Lynx, N/A
• Fits 1978-1979 Ford Fiesta, N/A

This part cross-references DENSO Auto Parts T20EPR-U15 and Ford AGSF24N for the same application.

Common Uses

• Replacing worn spark plugs that cause rough idle
• Restoring ignition consistency after misfire symptoms
• Addressing hard-start conditions tied to plug wear
• Improving combustion stability in high-mileage engines
• Servicing Ford Ranger, Explorer, Mustang, and related applications

Installation Notes

Verify thread diameter, reach, seat type, and heat range against the engine specification before installation. Check the gap against the vehicle service requirement even when the plug is pre-gapped, and inspect ignition components such as wires or coils if misfire symptoms are present. Use proper torque for tapered-seat spark plugs to avoid thread or sealing damage.

Quality Assurance

Denso manufactures this spark plug as part of its U-Groove Conventional ignition line, using specified electrode materials and resistance values for consistent secondary ignition performance. Confirm application by year, make, model, and engine specification before ordering.