I just replaced my oil cooler for the second time. Turns out the doorman gasket that came with my initial oil cooler was falling apart. I completely flushed the oil, pulled oil pan and valve covers and replaced after flushing the system 5 times. New CAT EC1 coolant and such.

Now, with the "upgraded OEM oil cooler" I drive my truck and my coolant never gets above 180, however, my EOT on the HWY reaches 223 which is a HUGE difference between delta's. I am way off the 15 degree variance.

What is going on??? I"M lost,

Any help would be appreciated!