The thermostat housing is located in the engine between the engine and the radiator. When the engine cools off below the operating temperature, the thermostat housing is closed.
The common symptoms of a thermostat housing leak are a stuck thermostat valve, an illuminated low coolant warning light, and the P0128 or P0125 code.
If the thermostat housing is broken or leaking fluid, it needs to be replaced as soon as you can.

Compatible with BMW E39 E46 E53 E83 E85 Vehicles:
2000 323ci 2.5L
1999-2000 323i 2.5L
2001-2006 325ci 2.5L
2001-2005 325i 2.5L
2001-2005 325xi 2.5L
2000 328ci 2.8L
1999-2000 328i 2.8L
2001-2006 330ci 3.0L
2001-2005 330i 3.0L
2001-2005 330xi 3.0L
2001-2005 525i 2.5L
1999-2000 528i 2.8L
2001-2005 530i 3.0L
2004-2005 X3 2.5L
2004-2006 X3 3.0L
2001-2006 X5 3.0L
1999-2002 Z3 2.5L
1999-2000 Z3 2.8L
2001-2002 Z3 3.0L
2003-2005 Z4 2.5L
2003-2005 Z4 3.0L

Replaces Part #: 11537509227, 11530139877, 902-813, 1430825, 432697D, 4326.97D Upgrade Aluminium Thermostat Housing Assembly.

NOTE: This is NOT a genuine part, it's a aftermarket replacement part manufactured by Allmotorparts.

NOTE: To ensure accurate fitment, please confirm your vehicle information in the above compatibility section and the description.