Bosch W7DTC Spark Plug - Waterboxer Engines (DF, DG, DJ Engine Codes) + T4 1800cc (PD Engine Codes)

Genuine Bosch W7DTC triple-electrode spark plug, designed for long life and superior ignition performance. Originally fitted to Volkswagen Type 25 (T3) Waterboxer engines (1900cc–2100cc) with DF, DG, and DJ engine codes, including fuel-injected models, this plug delivers enhanced combustion efficiency and durability under demanding conditions.

The triple-electrode design ensures a consistently clean spark path and extended service life by automatically selecting the best-ground electrode for firing. This technology reduces misfires, improves cold starting, and optimises fuel efficiency — ideal for classic VW engines that require smooth and reliable ignition.

With a 19mm long reach, 14mm thread, and copper-core electrode, the W7DTC offers excellent heat dissipation and spark stability. The M4 terminal type suits most standard VW ignition leads, while the 21mm spanner size makes installation straightforward.

Suitable not only for Type 25 Waterboxer models but also for a range of classic VW petrol engines including Mk2 Golf, Scirocco, and early T4 petrol variants.

Key Features:

• Bosch W7DTC triple-electrode spark plug – long-life design
• Correct fitment for VW Type 25/T3 Waterboxer (DF, DG, DJ) engines
• Triple ground electrodes for consistent spark and long service life
• Improved combustion efficiency and cold start performance
• Copper core electrode for reliable ignition under all loads
• 19mm long reach for Type 4 & Waterboxer applications
• Thread size: M14 x 1.25
• Spanner size: 21mm
• Terminal type: M4
• Sold each – 4 required per engine

Applications:

• VW Type 25 / T3 Waterboxer (1.9–2.1L, DF/DG/DJ engines, incl. fuel injection)
• VW Mk2 Golf (1983–1991) – 1.3, 1.8 GTI/GLI 8v, carb models
• VW Scirocco Mk2 (1984–1989) – 1.8 carb models
• VW T4 Transporter (1990–1992) – 1.8 petrol (PD)

Bosch Code Explained:

• W – 14mm thread diameter
• 7 – Heat range (2 = hot, 10 = cold; 7 = medium heat rating)
• D – 19mm long reach thread
• T – Triple ground electrode design
• C – Copper-core electrode material

Specification:

• Thread size: M14 x 1.25
• Thread reach: 19mm
• Spanner size: 21mm
• Terminal type: M4
• Electrode design: Triple ground
• Core material: Copper
• Quantity: Sold each