Should oil be going into radiator of a 1998 Chevy Blazer
Engine Oil should not be going into the radiator of ANY vehicle, including your 1998 Blazer. Radiator is for coolant ONLY. If there is oil in there, take it to your mechanic ASAP.
Oil in coolant, not good, possible blown head gaskets or cracked head. A "Block Check" test should be performed.
Do you mean seperate oil lines into the rad. The 1/2 ton and larger trucks had engine oil cooling lines running from above the oil filter to the rad (driverside of the rad). Usually on z-71's or truck with tow packages. Your Blazer may have this system. If it's an automatic the tranny cooling lines would connect to the opposite side of the rad. For these two systems the oil(s) run through coils in the sides of the rad and are imersed in the engine coolant. They are and must remain separate from the coolant.
Engine oil or trans fluid? Either way it's not good the transmission cooler is internal to the radiator and a full flush of the radiator and transmission along with new filter is required after replacing the radiator
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