So I put this simple filter system on my job1 6.4, truck has everything deleted and I run a tune from H&S for max MPG's. Truck has run strong modified for 2 years 30K. I put the kit on tested it 30 miles, checked for leaks and everything looked good. Pulling 13K up a grade the next day (I tow with 0 tune and keep it cool) I blew out both lower RAD hoses. I trouble shot everything in that system with 2 other mech's for 6 hr's before realizing that I had 0 trouble before the filter was installed. So I checked the kit and both hoses seemed to flow fine, I still have no idea why my system was being over pressurized. Deleted the kit and she is back to normal, $1150 later. I am NOT bashing sinister! I AM all ears on wtf could have put that much pressure in the system? MKM customs (sinister) was cool about the issue and have agreed to refund there product. Any Ideas? Similar circumstances?:argh::argh: