Mishimoto has developed a direct-fit replacement thermostat for the BMW M52, M54, and M56 engines. This Mishimoto thermostat is the ideal replacement for your failed stock thermostat. Our thermostat comes pre-installed in a durable OEM-quality housing and fits many BM Ws including E46, E39, and E85 chassis. Like all Mishimoto cooling products, this BMW M52, M54, and M56 thermostat is backed by our Mishimoto Lifetime Warranty. This Part Fits: Year Make Model Submodel 2000 BMW 323Ci Base 1999-2000 BMW 323i Base 1999 BMW 323is Base 2001-2006 BMW 325Ci Base 2001-2005 BMW 325i Base 2001-2005 BMW 325xi Base 2000 BMW 328Ci Base 1999-2000 BMW 328i Base 1999 BMW 328is Base 2001-2006 BMW 330Ci Base 2001-2005 BMW 330i Base 2001-2005 BMW 330xi Base 2001-2005 BMW 525i Base 1999-2000 BMW 528i Base 2001-2005 BMW 530i Base 2004-2005 BMW X3 2.5i 2004-2006 BMW X3 3.0i 2001-2006 BMW X5 3.0i 2001-2006 BMW X5 4.4i 2002-2003 BMW X5 4.6is 2004-2006 BMW X5 4.8is 1999-2002 BMW Z3 Coupe 1999-2002 BMW Z3 M Coupe 1999-2002 BMW Z3 M Roadster 1999-2002 BMW Z3 Roadster 2003-2005 BMW Z4 2.5i 2003-2005 BMW Z4 3.0i 2006 BMW Z4 Coupe 3.0si 2006 BMW Z4 M Coupe 2006 BMW Z4 M Roadster 2006 BMW Z4 Roadster 3.0i 2006 BMW Z4 Roadster 3.0si