I agree with Woody. The scale of an engine heat problem is so far above a CPU, that you would need ridiculous power (electrical) to run a TEC or Peltier that would be big enough to make a significant difference. Then the problem becomes where would you get all that amperage? The car's alternator isn't gonna cut it.

It's a great idea - the whole TEC or Peltier thing - but unfortunately, it's not gonna be achievable until we get superconductors and very high efficiency TEC or Peltier units.