The refrigeration fluid is vanishing I have to add it in a regular basis, I checked the system there is no leakage, and the radiator is ok. Please what could cause it?
Since its a 450 i'm going to go out on a limb and assume that it's a diesel. Your egr cooler can leak internally and cause coolant loss with no visible signs under the hood.
So as you said refrigeration, I am assuming that you mean the A/C system. There has to be a 134A leak somewhere or else the refrigerant would stay put, if you have already dyed the system and nothing was found in the engine compartment or out front then it is possible that it is the evaporator core inside the heater box itself, sometimes you can see it dye inside the drain hose, but the most common leaks on this type of rig is the condenser, usually a fracture in one of the tubes or fittings. HTH
Do you mean engine coolant? Anti-freeze?
EGR Cooler has an internal leak, head gasket, or cracked head.. Here in the USA we call it engine coolant.
By reading your other post about the trans leaking out of the vent tube you may have a crack in the trans cooler part of the radiator. that could make you loose coolant and overfill the transmission at the same time.
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