Agreed that the engine won't continue to "produce" heat after shutdown. That is, the hottest point in the engine (wherever that may be) will only get cooler. However, things near it may warm up.
I had an interesting example of the getting-hotter-after-removing-the-heat-source phenomenon a few years ago. We were injection molding some solid round b a l l s. Maybe 1.5" in diameter. The plastic material is injected at about 450-500F. The mold is cooled with roughly 80F water. A typical injection molded part is quite thin, relative to its surface area. These, however, were extremely thick, much more so than would be typical.
The plastic would be injected, and the parts would sit in the mold to cool, for quite some time (say a minute), so the outside would become firm enough that they could be ejected from the mold. During that time, the surface of the part is exposed to metal being cooled by 80F water. The center, however, is still very hot from the 450-500F plastic that you'd put in.
The interesting thing was that, when the parts were initially ejected from the mold, you could easily hold them in your hand. The outsides were warm, but OK. But wait 20-30 seconds, and you had to put them down, or you'd burn your hand. You'd removed them from the steel, which was drawing all the heat away. So as the remaining heat from the center (still at, say, 300F, to pick a number) continued to conduct outwards, the outer surface of the parts heated up a *lot*. This is in contrast to a typical-geometry injection molded part, which, to the touch, only gets cooler once it comes out of the mold.
Different context, but same phenomenon. No longer introducing any additional heat source (engine shut down), but remove some of the active cooling (airflow from flywheel), and the temperatures of some of the cooler areas will climb as things equalize.
This message was modified Mar 22, 2012 by RedOctobyr
