Well after reading all the responses I decided to put my two cents in.

What I came up with is easy and all the part are off the shelf parts.

If any of you ride Harley you would know we have a temperature  problem
also.
As long as the bike is moving, no problem, but once you have to sit in
traffic on a hot sunny day you will over heat. To solve this they have
come up with a after market oil cooler.

So all you need to do is get an oil cooler attach a inline fuel pump,
wrap the servo in some aluminum tubing, fill it with water and or
anti-freeze. This way you will be able to cool the servo. Just be sure
to put the cooler where air will flow over it. Add a fan if your not
getting enough air across the cooler. You can also add a thermostat to
control it even more.

Hope this helps..

Jeff