I live in the middle of the Sierra mountain range in CA, thus I get lots of experience with some pretty steep grades. There are lots of places where I'll be going 50 or so up a hill and the temp gauge is reading a little above 100. This last year I changed out the coolant and flushed the system and cleaned out the "between the fins" area of the radiator - lots of really fine dirt in there... . I saw lower around town and cruising on the level highways temps, but the same temps as before the change out on some of the steep grades. It now reads a little above 80 for normal operating temp.

Something weird did happen the other day though, maybe someone can shed some light. Heading up the Cajon grade the other day, pretty steep (don't know the exact grade) for about 20 miles or so at around 60-65 MPH. Shortly before the top the low coolant light comes on. I pulled over as soon as possible, a little past the summit on the downhill grade. Temps never went beyone 105-110 according to the gauge. By the time I popped the hood and looked I had a full reservoir of fluid. Everything else looked fine and temps read a little over 80. I closed the hood and drove the 100 miles home. Any thoughts on what happened? I'm not leaking any coolant (since the H2O pump replacement, anyway) and I don't have any pressure in top hose prior to starting in the morning.

__________________
-livin' in the terminally flippant zone