Spark plug Bosch NOS W7DC WR7D WR7DC – Mercedes M110 M116 M117

Description

Bosch NOS spark plug W7D W7DC WR7DC and WR7DC+ – original Bosch Made in Germany – highest quality

This original Bosch NOS spark plug is an unused spark plug from old factory stock, produced in Germany. The spark plug is manufactured according to the original Bosch specifications and quality standards from the period when these classic Mercedes engines were still in production.

The Bosch W7D, W7DC, WR7DC, and WR7DC+ are among the spark plug types prescribed for various classic Mercedes petrol engines. Thanks to the original material selection, precise manufacturing, and constant heat dissipation, these spark plugs ensure reliable ignition, smooth engine operation, and optimal combustion.

Original Bosch spark plugs from the former German production are becoming increasingly difficult to obtain. Good old factory stock is becoming scarcer, causing prices to rise. For enthusiasts who wish to maintain or restore their Mercedes as close to the original as possible, these Bosch NOS spark plugs represent the best and highest quality available.

This spark plug is suitable for various versions of the Mercedes M100, M110, M114, M115, M116, M117, M130, and M180 engines, among others. Multiple versions, compression ratios, and ignition systems were used within these engine series. Therefore, always check which spark plug type is prescribed for the specific engine before purchasing.

Suitable for Mercedes models

• Mercedes C107 280 SLC (107.022)
• Mercedes C107 350 SLC (107.023)
• Mercedes C107 450 SLC (107,024), European version, not North American version

• Mercedes R107 280 SL (107.042)
• Mercedes R107 350 SL (107.043)
• Mercedes R107 450 SL (107,044), European version, not North American version
• Mercedes R107 420 SL (107.047)

• Mercedes W108/W109 300 SEL (109.016)
• Mercedes W109 300 SEL 3.5 (109.056)
• Mercedes W109 300 SEL 6.3 (109.018)

• Mercedes W114 230.6 (114.015)
• Mercedes W114 250 2.8 (114.011)
• Mercedes C114 250 C 2.8 (114.023)
• Mercedes C114 280 C (114.073)
• Mercedes C114 280 CE (114.072)

• Mercedes W116 280 S (116.020)
• Mercedes W116 280 SE (116.024)
• Mercedes W116 280 SEL (116.025)
• Mercedes W116 350 SE (116.028)
• Mercedes W116 350 SEL (116.029)
• Mercedes W116 450 SE (116,032), European version, not North American version
• Mercedes W116 450 SEL, European version, not North American version

• Mercedes W126 420 SE (126.034)
• Mercedes W126 420 SEL (126.035)
• Mercedes W126 560 SE (126.038)
• Mercedes W126 560 SEL (126,039), European version, not North American version

• Mercedes C126 380 SEC (126.043)
• Mercedes C126 560 SEC (126,045), European version, not North American version

• Various other classic Mercedes models with the engines listed below.

Suitable for Mercedes engines

• M100
• M110
• M114
• M115
• M116
• M117
• M130
• M180

Suitable for the following engine codes, among others

• M100.981
• M110.921
• M110.922
• M110.932
• M110.981
• M110.982
• M110.983
• M110.985
• M110.986
• M110.990
• M110.993
• M116.963
• M116.964
• M116.965
• M116.981
• M116.982
• M116.983
• M116.984
• M117968
• M117982
• M117983
• M117985
• M117986
• M130.923
• M130.981
• M180.954

Specifications

1. Part: original Bosch NOS spark plug.
2. Brand: Bosch.
3. Bosch types: W7D, W7DC, WR7DC and WR7DC+.
4. Origin: Made in Germany.
5. Condition: unused part from old factory stock, New Old Stock.
6. Thread size: M14 × 1.25.
7. Thread length: 19 mm.
8. Wrench size: approximately 20.8 mm.
9. Seal: flat sealing ring.
10. Center electrode: nickel.
11. Number of ground electrodes: 1.
12. Produced according to the original Bosch specifications.
13. Original Bosch quality from the German production period.
14. Highest and best quality available.
15. Ideal for maintenance, overhaul, and original restorations.
16. Always replace spark plugs as a complete engine set.

OEM references

• A0031591203 / 0031591203
• A0031592603 / 0031592603
• A0031594503 / 0031594503

Important

Before purchase and installation, always check whether the Bosch type, the prescribed heat number, and the version correspond to the specifications of the engine in question. Different compression ratios, ignition systems, and spark plug specifications have been applied within the mentioned Mercedes engine series.

Not every Bosch W7D, W7DC, WR7DC, or WR7DC+ spark plug is interchangeable without verification. The versions may differ in terms of interference suppression and connection, among other things. Therefore, always compare the Bosch part number and version with the installed spark plug and the Mercedes factory specifications.

Electrode gap

Always check the prescribed electrode gap with a feeler gauge before installation. The correct gap depends on the engine code, year of manufacture, compression ratio, and ignition system design.

Adjust the electrode gap exclusively according to the Mercedes factory specifications for the specific engine. Even original Bosch NOS spark plugs may have a different electrode gap due to prolonged storage, transport, or previous handling.

Pre-assembly inspection

Carefully inspect each spark plug for damage from transport, storage, or falls before installation. Dented or damaged 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, only install spark plugs with completely undamaged ceramic.

Replacement advice

We recommend replacing the spark plugs preventively every 8 years or 30,000 kilometers, whichever comes first. Even in vehicles that are driven infrequently, the electrodes and insulation material can deteriorate due to aging. This can lead to a weaker spark, rough engine operation, higher fuel consumption, and poor starting.

For optimal performance, we recommend always replacing the spark plugs as a complete engine set. Simultaneously check the condition of the spark plug wires, spark plug caps, distributor cap, and distributor rotor to prevent voltage loss and ignition malfunctions.

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.