hoping Mike can help or maybe some others might have some ideas too.

i had e-fans on my truck all last year and never had any overheating problems when pulling my boat.

this year i installed the underdrive pully i got from TP and everything seemed fine.

the next day i got to tow my boat and after running down the road for a half hour and stop the oil pressure guage starts bouncing alittle. just off idle it is back to normal. then going uphill i could whatch the temp guage start climbing never had that problem before.

so my question is should set up fan turn on temp lower? or is the under drive turning my water pump too slow at 2000 rpm to keep the motor cool when im towing?

its a 97 4.2L V-6 5-speed with towing package

 

I would say the underdrive pulley is the problem. Didnt happen before you changed pulley, right?

Your water pump is not turning as designed to do w/OEM pulley. JMO! Look for updates as Im not sure on alternatives besides going back to oem pulley.

Good luck...OT