yesterday pulling 4k with my 05 6.0 for the first time i had a delta of 7to10* around town stop and go traffic.Once i got to a 1/4 mile long farley steep grade i got an ECT of 200-208 and a EOT of up to 218*at one point my delta was over 15*. Normal delta is around 7-10* empty no flat areas in NH.Now last weekend i did a coolant flush on a motor with 8k on it just wanted to put elc EC-1 coolant in for sure.When i got to my house i popped the hood to notice my coolant resi was chuck full.Also what temp should my fan come on at?Thanks for all the help.