i have found over the years that the #1 reason for heat problems is rad thickness. i went to a z-core back in 90 with an original 47 rad. you could see through it and only 2 3/8 in thick. was able to move much more air at idle. sold the walker to the first person i could and have not owned one since. since then i have switched to aluminum rads and the flexlite cyclone fan . my shop truck will have a ford factory electric fan from a 94 tbird. thing is like a helicopter but draws a lot of amps.