I took my electric off (former owner installed) , because it was supposed to be a 'helper', and only slowed air to the radiator ( installed in front of it)...after I removed it , 5F less,
after I added X fillers 10F less, after I installed the missing on right side rubber filler ( factory called "masticated") another 5F less...so it went from 220-225F to 195-200F... now with using the "improved" spacer/divider inside the waterpump at the impeller it stays at 195F summer, 165-170 winter...