a lot folks with 05 LLY's have helped solve the issue with putting the less restrictive LBZ Turbo mouthpiece in it's place and a aftermarket air intake or modify the Existing one to get more cool air
http://www.duramaxforum.com/forum/04...g-problem.html but then some folks never had a problem with their LLY overheating and some folks Never solved it seems to be Random but other than the 05 LLY it has not been much of a Issue on the Duramax as they made improvements to the Turbo Mouthpiece, radiator and fan etc.. on the 06 and up D Max's and I have owned 2 and have friends with 01's all the way to newer D Max's BUT make no mistake I have been up some Nasty Grades in Colorado and Utah in Hot weather and My LBZ and my old LB7 did get close a few times to the Danger Zone but the bottom line is a scooter on the front has made No difference in cooling on mine,I love my Duramax's but I would not buy a 05 LLY it was a funky year for them