TOPRAN spark plug (503 201) fires the air-fuel charge with a precisely controlled spark at the correct electrode gap and heat range for your engine's combustion chamber geometry. Plug parameters — Spark Plug: 30, Supplementary Article/Info 2: 846 — determine ignition timing accuracy, electrode longevity, and resistance to pre-ignition deposits across the full RPM range. Thread reach, seat type, and hex size are specified to fit BMW cylinder heads without re-gapping or thread chasing. Replaces OE ignition references: 0 242 140 507, 0 242 140 560, 1212 0 034 091, 1212 0 038 349 and 13 more. TOPRAN ignition components are manufactured to SAE and DIN specifications and are approved for use in vehicles covered by manufacturer service agreements throughout Europe. Standard copper-core spark plugs last around 20,000–30,000 miles, while iridium or platinum-tipped plugs can last 60,000–100,000 miles — always follow the interval specified in your vehicle's service schedule. Symptoms of worn spark plugs include rough idling, engine misfires (often felt as a stumble under acceleration), increased fuel consumption, and difficulty starting in cold weather. Spark plug replacement is a straightforward DIY job on most engines — you need a spark plug socket, a torque wrench, and a gap gauge; allow 30–60 minutes for a four-cylinder engine, longer for boxer or V-configurations where access is tighter. Always match the heat range and electrode material specified by your engine manufacturer — fitting a plug with the wrong heat range can cause pre-ignition, fouling, or catalytic converter damage. Replacing spark plugs on schedule maintains optimal combustion efficiency, reduces harmful emissions, and prevents unburnt fuel from damaging the catalytic converter — a component that costs many times more to replace. Every part is dispatched from our UK warehouse with a 30-day money-back guarantee and free hassle-free returns.

TOPRAN, part of the Hans Thomsen Group headquartered in Hamburg, Germany, is a growing independent aftermarket brand focused on providing quality parts at accessible prices. TOPRAN offers a comprehensive range covering engine, cooling, electrical, braking, and body components for European vehicles. All TOPRAN products are manufactured to meet OE specifications and undergo quality testing before distribution. Combining German quality management with competitive pricing, TOPRAN is an excellent choice for cost-conscious motorists and workshops who do not want to compromise on part quality.