This part is listed by BMW as BMW part number 11531265085 (11-53-1-265-085) and is described as OEM Engne Thermostat for E30 325e/325es (1984, 1985) and E28 528e/524td (1982, 1983, 1984, 1985).
This Thermostat is a high-quality OEM replacement piece for your E28 5-Series or E30 3-Series. This original equipment unit assures perfect fit and functionality.
We highly recommend replacing your temperature thermostat as a preventative measure anytime you perform a full cooling-system service.
E30 (84-91) > 325e
E30 (84-91) > 325i
E30 (84-91) > 325ix
E28 (82-88) > 524td
E28 (82-88) > 528e