The O-ring K 70016 is a small but essential sealing element used with the oil pump K 71001 on the Sulzer ZV40/48 engine. Designed from heat- and oil-resistant elastomer, it prevents oil leakage at the pump joints and maintains system pressure under continuous operation. Although inexpensive, this O-ring plays an outsize role in avoiding contamination and preserving lubrication integrity — a quick visual check and timely replacement during scheduled maintenance will prevent costly oil loss and downstream damage.