View 5 Photos View 0 Videos 1978 Mack RD685S Intercooler Contact for price (Used) 1978 Mack RD685S, INTERCOOLER- Part Number: 735G856, Serial Number: 105GC55170, Engine: 1977 Mack ENDT-676, Dimensions: L=15", H=8",, For more information about this item, give us a... ConditionUsedEngine ModelMack ENDT676Fits To Make(s)MackFits To Model(s)RD685SWill Fit Year(s)1978Part Number735G856Stock NumberP-84914 MLS Number13016934CategoryIntercoolers Last Updated5/13/2026 LocationElkton, MD, US Sold ByCRG Heavy Truck Parts (844) 402-___ SHOWNUMBERCall Seller Email Seller Save More Info