BMW Coolant Thermostat. Fits the following models:

    5' E12   (06/1973 — 07/1981)
    5' E28   (09/1980 — 12/1987)
    2.5CS-3.0CSL   (12/1968 — 11/1975)
    6' E24   (10/1975 — 04/1989)
    2500-3.3Li   (08/1968 — 02/1977)
    7' E23   (10/1976 — 06/1986)
    M1 E26   (06/1980 — 07/1981)