Had my viscus cluch replaced about two weeks ago and noticed almost 1/2 mpg increase on my 03 international DT466E didnt even realize that would even be an issue. I swapped it out because it was running hot especialy on long pulls on hills and when the T stat was swiched at the dealership tech told me the bi-metal spring was crudded up and needed to be cleaned charged me an hour he quoted me five hundred bones for a new fan cluch plus labor ummmm., no way. So, I spent a couple weeks keeping an eye on it and noticed some play in the rear bearing and just a little of what looked like a dis-coloration but not leaking. Again nothing earth shatering except one time I noticed more play in the bearing especialy when hot at this piont it was abbout 3/4" at the blade tip. My mechanic told me viscus cluches can be verry tricky because most people don't catch the warning signs untill the fan goes through thier radiator. As with mine, it probably started leaking at the bi metal spring where of corse you cant see it. Here's some of the things to look for.
Over heating or running hot espicialy in city driving or idling keep in mind most aplications only kick on at 190-220 deg.F and kick off 160-170 deg.F temp range varries year, make, and model
Over cooling or just not getting up to temp when cold out.
Un explained drop in mpg that dosen't match driving habbits or terrain your driving in usualy only 1/2 - 2 mpg milage like driving in hilly terrain if that helps this one is hard to tag it passed me.
Another symptom is power loss not realy noticable unless your super in tune with your rig or the fan cluch suddenly craps out on you.
Exessive noise when cold that dosent go away after idling a couple minites you can usualy hear it at idle and as you accelerate fan is locked up.
Quiet fan when hot you should hear it blowing or engine tone change as you accelerate excessive spin when you shut it down.
Most of us know what our rigs sound like so if it dosen't sound right check it out.
Discoloration, staining, or leaking at the rear bearing or bi metal spring newer design have a weep hole kinda like a water pump
also look for whitish or greyish spltters inside the radiator schroud.
Play in bearing GET THIS ONE FIXED A.S.A.P. it will soon go through your radiator, intercooler, A.C. condenser, trany cooler, engine oil cooler, as well as destroy your fan and other parts within reach of the fan. With todays trucks being computerized and emisions it gets worse trust me I've seen it, and its not pretty.
If you notice you dont have the output or milage you had, or its running hot check the viscus cluch.
BTW Ryder fleet services has decent prices if they carry it so you dont get screwed by the dealer for example the dealer wanted $ 285.00 Ryder $ 185.00 with shipping
Last edited:
