O ring set for engine cooling system quick connect hoses For BMW e85 / e86 Z4 N51 / N52 2.5 Si, 3.0Si, 3.0i engine AUTOMATIC Or MANUAL The O rings for the quick connect hoses are not carried by dealers. In most leaking situations the hoses are perfectly fine, and the leak is caused by dry O rings, which can be replaced with this affordable set This set is made of NBR material (same material as the original ones) ////////////// Fits BMW Below: 2006 to 2012 Z4 3.0Si 2.5 N52 / N51 Engines 2007 to 2012 Z4 3.0i, 2.5 N52 N51 Engines