Hi, everybody. I bought a 1989 Isuzu Trooper II, with the 4 cylinder engine, a few months ago. So far, I love it. I live in Arizona (can you say "hot in the summer"?). In returning home from where I do my shopping, I have to climb over a mountain range. About 10 miles up a pretty good grade. In most "normal" driving, the temp gauge comes up to about 1/4 of the way. When climbing the mountain, the gauge goes up to around 1/2 way then, of course, comes back down shortly after cresting the pass and starting down. When I drive off road, low range, slow speed and higher rpms, the gauge will go up to around 2/3 of the way. Does this behavior sound normal, or should I be concerned about it and have the radiator checked. I don't want excessive heat to cause engine problems. The radiator looks fairly small, and this temperature fluctuation may be normal and not out of the ordinary. Just asking other owners what they think. Thanks, in advance, for any info and opinions. Oh, and yes, the radiator is full with a mix of distilled water and anti freeze - coolant.