Set of 4 iridium spark plugs NGK 97566 SILZKFR8F7S Mercedes-Benz A/C/E/S-Class M274 M270

Set of 4 NGK 97566 SILZKFR8F7S Iridium Spark Plugs for Mercedes-Benz A/C/E/S-Class M274 M270

High-tech solution for Mercedes-Benz engines

The NGK 97566 iridium spark plug set (part number SILZKFR8F7S) is a set of four original plugs from the premium Laser Iridium series. These components are specially designed to ensure stable operation of modern turbocharged Mercedes-Benz engines of the M270 and M274 series. The main advantage of the series lies in the use of a combination of two precious metals: an ultra-thin iridium tip on the central electrode and a platinum pad on the ground electrode. This design guarantees the highest resistance to electrical erosion and oxidation under conditions of extremely high temperatures and pressure in the combustion chamber.

Stable ignition and fuel economy

The use of iridium allows the diameter of the central electrode to be minimized, significantly reducing the required ignition voltage. This ensures confident cold engine start and prevents misfires at high revs. Laser welding of the electrodes creates the most precise spark gap geometry, promoting rapid and complete combustion of the air-fuel mixture. As a result, the car owner gets smoother engine operation at idle, improved acceleration dynamics, and reduced fuel consumption. The presence of a built-in resistor with a resistance of 5 kOhm effectively suppresses electromagnetic interference, protecting the car's onboard electronics from malfunctions.

Reliability and service life

The metal body of the plugs is protected by a special trivalent zinc anti-corrosion coating, which prevents thread seizing and facilitates removal even after prolonged use. The high-density ceramic insulator has excellent dielectric properties, eliminating the possibility of voltage breakdown to the body. The extended shape of the threaded part and the specific cup-type connection ensure reliable contact with the ignition coil and perfect sealing of the spark plug well. The service life of the iridium set significantly exceeds standard nickel counterparts, reaching 80,000 – 100,000 kilometers depending on operating conditions.

Installation recommendations and compatibility

The plugs are intended for Mercedes-Benz gasoline engines with a displacement of 1.6 and 2.0 liters. This set is a direct equivalent of factory parts with OEM numbers A0041598103 and A0041597503. During installation, it is critically important to observe the tightening torque (15–25 Nm) and use a specialized 12-point spark plug wrench of 14 mm. Proper installation prevents damage to the ceramic insulator and ensures correct heat dissipation from the combustion chamber to the cylinder head.

Technical specifications

• Brand: NGK

• Brand registration country: Japan

• Material: iridium, platinum, ceramic, nickel-plated steel

• Size: thread diameter 12 mm, thread length 26.5 mm, wrench size 14 mm (12-point)

• Color: silver metallic, white

• Weight: 192 grams (set weight)

• Condition: new

• Product group: spark plugs for passenger cars

• Purpose: ignition of the fuel mixture in Mercedes-Benz gasoline engines

• Compatibility: Mercedes-Benz A-Class (W176, W177), B-Class (W246, W242), C-Class (W204, W205), E-Class (W212, W213), S-Class (W222), CLA (C117), GLA (X156), GLC (X253), GLE (W166), SLK (R172) with M270, M274 engines

• Package contents: NGK 97566 spark plug — 4 pcs., individual packaging

• Plug type: Laser Iridium (iridium-platinum)

• Features: iridium central electrode, platinum insert on the side electrode, 5 kOhm resistor, laser welding, copper core for better heat dissipation

• Heat range: 8

• Thread pitch: 1.25 mm

• Electrode gap: 0.7 mm

• Connection type: cup-type

• Seal type: flat with gasket

• Correspondence to OEM numbers: A0041598103, A0041597503, A0041597203, 0041598103, 0041597503, 0041597203