Description Detroit Diesel Fan Clutch Replaces OEM: 991064 Kit Masters’ HT/S-style remanufactured fan clutches feature vastly improved materials, compared to the OEM. Our Viton® o-rings withstand temperatures up to 400° and resist drying out. Dramatically stronger friction material sustains more fan clutch engagements and will not shear away from the backing plate. Application Freightliner / Detroit Diesel Series 60 Kenworth / Detroit Diesel Series 60 Volvo / Detroit Diesel Series 60 Sterling / Detroit Diesel Series 60   *There is a $250 core charge. Cores can be returned for a $250 refund. Fill out and print the form below and add it to the return box, send cores to: SP Truck Parts Core Return 30026 Beverly Rd Romulus MI 48174   Fan Clutch Core Return Form