Block heaters do not have thermostats (unless you scored something fancy )

I used a 10amp rated timer from fred meyers or something from the sort....its just one of those little cube shaped ones and seems to be working pretty good

Block heater comes on about 10-11pm and stays on until about sunrise....I have non-antifreeze water in my intercooler at the moment so I can't risk a freeze. I'll eventually put some antifreeze in there but I still have work to do

I am using this exact timer: http://www.homedepot.com/prel80/HDUS/EN_US/diy_main/pg_diy.jsp?CNTTYPE=PROD_META&CNTKEY=misc%2fsearchResults.jsp&BV_SessionID=@@@@1012405421.1140112402@@@@&BV_EngineID=ccgkaddhddlkfeicgelceffdfgidglo.0&MID=9876 Its rated at 15amps and 1750watts