Hi, New To The Whole Forum Thing But Thought It Was Worth A Shot, So Here Goes; 89 Chev Dually 454, Motor Runs Great Cooling System Tight,180 Hi Flow Stat, Custom 5 Row Radiator Cleaned Last Week, New Ac Condensor(old One Fins Were Bent Pretty Good), Problem Is It Still Overheats With The Ac On ( It Has Been 108 Degrees This Week) The Only Thing That Keeps It Cool Is If I Use A Clutch Fan Eliminator Then The Thing Stays At 180 But The Cheap Stock Pulleys Crack. I Have Tried Every Clutch Fan On The Market And 2 Oem"s They Just Won't Do It. So It Seems To Be An Airflow Isssue Not A Mechanical One, Someone Said You Could Drill And Pin The Clutch Fan But I Wouldn't Where To Drill Plus I Would Be Afraid The Bearing Would Sieze And Cause More Issues Has Anyone Heard Of This. I Would Like To Find A Billet Eliminator And See If That Does It Instead Of The Cheapy Pot Metal Stuff, Open To Ideas Help... Thanks
ok I understand your problems. the clutch fans came in a heavyduty version that are hard to find. your best bet is to use a steel flex fan with a 2" spacer and block off the elbow hose from your intake to your waterpump, this forces all fluid through your radiator and does not bypass any. the flex fan is much easier on your pulley system and safe up to 6K RPM's.
Honestly if it was me I'd install a small 12" electric pusher fan to help out only when the A/C is on. If you are sure that you are using the correct HD fan clutch then that is what I'd do. The electric fan will help make the A/C work better and get cold almost emmediately when you start it. When you say you are overheating, how hot is it actually getting?
89 I'm Guessing it has HEI, Check to see if you timing is set to factory spec's. Is the fan shroud COMPLETE and intact? I wouldn't mess with a flex fan, Go to the dealer and buy the correct fan clutch, make sure your running 50-50 coolant.
it will keep walking up past 225 and it has an oem pusher acc fan and i've ran 2 oem fans that don't work (the orig part number was supersceeded to what I believe to be an inferior unit to the orig. unit and then like i said tried all the aftermarket junk to no avail. also the shroud is intact and and i even went so far as replacing the fender rubber skirts in case air was sneeking around. The weird thing is like i said earlier when i had the eliminator on it cured the overheat problem to the point i had to go back 1 step warmer in my thermostat, but then I started cracking waterpump pulleys and got stranded so that was enough of that. one guy said something about drilling the clutch fan?????
I'd get an aftermarket pully and put on the eliminator then. If you take that spring off od the fan clutch it's supposed to stay locked up. Regardless, that doesn't sound right. It should be able to stay cooler than that idling with the A/C. My '81 454 does just fine idling with the A/C. Who knows though, I have a friend with a '95 3500 with a 454 and it ran 210-245* ALL the time. Never leaked oil, never burned any, and always ran good. GM just told him to drive it when he complained about the temps.