Thermostat O-Ring, Genuine BMW - E46 M3, MZ3 S54, Z4M

This part is BMW part number 11531318402 (11 53 1 318 402) and is the o-ring seal between the thermostat and the water pump housing on S54 engines in the E46 M3, MZ3, and Z4M. The S54 engine was used in model years 2001, 2003, 2004, 2005, 2006 (as well as Z4 M into 2007 and 2008).  It also fits the Euro S50 engine used in E36 M3. 

This o-ring measures 64.77 X 2.62 mm (About 2.5 inches in diameter, and about 1/10th of an inch in thickness). 

This is a Genuine BMW thermostat o-ring, the same you'd get a BMW dealer, only at a better price and the convenience of shipping direct to your door. As the authentic BMW part, you are assured it meets all of BMW's original design, fitment, and performance requirements and is German TUV approved. Original BMW o-rings and parts are a "known good" and offer premium brand assurance for a slightly higher cost. 

For full BMW fitment information or for assistance from one of our BMW experts, we recommend calling us at 877-639-9648.