I used that technique when I was driving up the steeper grades. On one crazy steep and sustained grade in Nevada, I had the heat on full blast, windows down, AC off and the lowest I could get my engine temp was 208. It wasn't fun doing this but it was better than the other option of pulling off on the side of the highway to give the engine a break and cool off a bit.

This was my worst driving experience ever in one of my rigs. But, knowledge is power. If I wasn't monitoring my engine temps, I could have been one of the many people we saw stranded on the side of the highway that had no clue they were overheating their engine. Our analog temp gauges are pretty much worthless. By the time the needle starts to rise, you've already overheated your engine big time. On the trip, there was no difference in needle position from an optimal 188-192 engine temp and the high of 212 I got my engine to.