Firewall, inboard of the battery.

http://www.google.com/imgres?imgurl=http://www.dieselgiant.com/monovalve48.JPG&imgrefurl=http://www.dieselgiant.com/coolingsystem.htm&usg=__u34H50oRLjZHdFjRYLwFcxGPx6o=&h=480&w=640&sz=66&hl=en&start=0&zoom=1&tbnid=qMvxvNPPjr4FBM:&tbnh=170&tbnw=227&prev=/images%3Fq%3D300d%2Bmonovalve%26um%3D1%26hl%3Den%26client%3Dsafari%26sa%3DN%26rls%3Den%26biw%3D1647% 26bih%3D831%26tbs%3Disch:1&um=1&itbs=1&iact=rc&dur=439&ei=bw7STPyMFYG0lQfyoPC1Dg&oei=bw7STPyMFYG0lQfyoPC1Dg&esq=1&page=1&ndsp=28&ved=1t:429,r:5,s:0&tx=129&ty=93