PART NO. 7L3Z-8575-B7L3Z8575B/ 7L3Z-8575-C7L3Z8575C/ 7L3Z-8575-D 7L3Z8575D / 7L3Z-8575-E 7L3Z8575E. ENGINE COOLANT THERMOSTAT. THERMOSTAT TEMPERATURE = 192.02F / 88.9C . MOTORCRAFT PART NO.RT- 1196 RT1196 / RT-1229 RT1229 / RT-1234 RT1234 /RT-1254 RT1254.