Spark plug BOSCH NOS M117 and M116 WR9DC – Mercedes R107 W126 380SL 560SL USA

Description

Bosch NOS spark plug WR9DC / WR9DC0 – original Bosch quality – Mercedes M116 and M117 V8 engines

This Bosch NOS (New Old Stock) Spark plug WR9DC / WR9DC0 is an original Bosch spark plug from old stock and is manufactured according to Bosch's high quality standards from the period when these spark plugs were fitted as standard in many Mercedes V8 engines. These spark plugs are produced in Germany and are known for their excellent finish, reliable ignition, and long service life.

The original Bosch WR9DC and WR9DC0 spark plugs were prescribed by Mercedes for various M116 and M117 engines with a lower compression ratio, including various export and USA versions.

Original Bosch NOS spark plugs are currently only available in limited quantities and are becoming increasingly rare. For enthusiasts who want to maintain their Mercedes as close to original as possible, these spark plugs are therefore the best choice.

Suitable for, among others

• Mercedes R107 380 SL
• Mercedes R107 560 SL (USA version)

• Mercedes W126 380 SE / SEL
• Mercedes W126 560 SEL (USA version)

• Various Mercedes models with M116 and M117 engines with a lower compression ratio.

• Various export versions outside Europe.

Specifications

1. Brand: Bosch.
2. Type: WR9DC / WR9DC0.
3. Original Bosch NOS spark plug from old stock.
4. Made in Germany.
5. Thread size: M14 × 1.25.
6. Thread length: 19.0 mm.
7. Wrench size: 20.8 mm.
8. Flat sealing ring.
9. copper center electrode.
10. One ground electrode.
11. Uninterrupted execution.
12. Mercedes OEM alternative: A0031591003 / 003159100326 / 0031591003.
13. Price is per piece.

Advantages

1. Original Bosch NOS quality from old stock.
2. Produced in Germany according to the original Bosch specifications.
3. Identical spark plug type as used at the factory at the time.
4. Reliable ignition and smooth engine operation.
5. Ideal for original restorations and classics.
6. High collectible and use value due to limited availability.

Important

Before installation, always check that the prescribed heat number matches your engine specifications. In particular, different spark plug types may be prescribed for European and American versions of the M116 and M117 engines.

In case of doubt, we recommend checking the original Mercedes part number, engine number, or the engine compression ratio.

Always carefully inspect new spark plugs for transport or fall damage before installation. A dent or damage to the packaging may indicate that the spark plug has been hit hard. As a result, the ceramic insulation part may contain invisible hairline cracks.

Damaged ceramic can come loose during use and end up in the combustion chamber, potentially resulting in serious engine damage. Therefore, install only spark plugs with completely undamaged ceramic.

Always check the spark plug electrode gap before installation. For most Mercedes M116 and M117 engines, an electrode gap of 0.8 mm recommended. Check each spark plug with a feeler gauge and correct the gap if necessary according to Mercedes factory specifications.

We recommend replacing spark plugs preventively every 8 years or 30,000 kilometers to replace, depending on which is reached first. Even in vehicles that are driven infrequently, the electrodes and insulation material can deteriorate due to aging, which can lead to a weaker spark, rough engine operation, higher fuel consumption, and reduced cold starting.

Always check before purchase and installation whether the part is suitable and equivalent based on photos, description, and specifications; installed or used parts cannot be returned.