i say its due to the body lift and movement of the fan shroud, your shroud is now 3"down from where it is supposed to be or has a 3" gap in it, nobody else has had this issue that i have seen. I too would get some ls1 fbody fans, sure it would entirely fix the problem. You have a bigger motor with high compression, that makes more heat than a stock 5.3, people don't realize that a v8 isn't a v8, more hp=more heat. And that watter wetter and such is a gimmick. it is good for drag racing because it isn't slippery and if you blow coolant on the track you won't be hated by everyone while it takes an hour to clean up. We have tried it in boss hoss bikes at work and it doesn't do a thing for lowering temps.

 

That is a good theory, I appreciate the feedback, but I have had the body lift on the truck for over a year with no issues.... Obe thing i noticed is The fan seems tighter than it used to be

 

Remember, in your case, it's not just one thing, it's a combination of your setup, along with slowing down the fan & coolant flow with the UD pulley. The E-fans in the classifieds should cure your troubles, and give you a couple hp at the same time.

Don't give up and sell your pulley, get the Efans. You'll be glad you did.

 

ok il try that you talked me into it LOL! You think the ls1 fbody fans would be good enough?

 

Absolutely.

 

Don't be so quick to condem your UD Pulley. I've been running one on a 99 for 10 years and the temp rarely gets above 185 unless I'm in stop and go traffic w/AC "ON" in the heat of summer. I installed Flexalite elec fans(one pusher and one puller and I don't even have a fan shroud). I used 2 relays to turn the fans "ON". One triggers off of the ECT and the other off of the AC clutch relay. If you use factory fans you can use the PCM as a trigger. I'd do the 160 T-Stat and elec fans and then see what happens. I'm also running a Meziere so maybe that helps keep my water temps down, but those things cost about $600.00 which may be a little steep to get your water temp down a few degrees.