Read the link genious they do the opposite of what your saying they actually produce alot of heat.
From the link
LEDS use small diodes that produce light when electric current excites their electrons. They need an low amount of power to work but do produce a significant amount of heat on the diode. This requires heat control systems at the bottom of the headlight and near other car components. If this system fails, not just the light, but other electronics could be affected.
The small size of LEDs means they can be formed into almost any shape, and their light is naturally directional rather than diffuse, making them an excellent choice for headlight