Is it normal for our cars to get hot while going up steep hills? The high was 89 degrees today, and I started noticing my temperature gauge beginning to climb above normal while driving up highway 421 towards Boone, NC. There's a big hill between Wilkesboro, NC and Boone, NC. This stretch of highway is listed by the NC DOT as having an 8% grade for 4 miles.
The farthest the temp needle would go was almost to the 3/4 mark. This was with the heat running full blast on recirculation mode and the windows down (I instinctively blasted the heat. I don't know how hot it would've gotten with no heat on). Speed was about 65mph up the grade. The auto trans cycles between 3rd and OD at this speed, with the average RPM at about 4000-4500.
Is this something I should worry about? I don't have any coolant leaks, and have zero cooling problems while driving on normal roads and highways. This stretch of 421 is unusually steep and causes people to go pretty slow (on average, 10-20mph under the posted 55mph speed limit). The engine was still pretty hot after cresting the hill, and didn't really reach the normal temp again until I had driven about 2-3 miles on flat highway. I replaced the thermostat last August. The coolant level is "full", and the coolant itself is about 2 years old. The odometer reads 142,000 miles.
Thanks!!!