Your 1989 Toyota 4WD Pickup overheats even though you changed the radiator thermostat tensioner belt bearings and water pump and the oil is not milky at all?

Ok ....Have you changed the thermostat? It could be worn and sticking,thus holding it open also another thought.. new radiator cap. If it is worn out, it cannot help hold the pressure inside the radiator and engine, therfore the fluid(50/50) is dumped out thru the overflow pipe.(My dad was a hotrod engine builder)I have a 1998 blazer and I had to do the same thing.New radiator because the tensioner broke off and ran thru the radiator.New upper and lower hoses. New thermosatat, couldn't figure it our until I looked at the radiator cap. 16lbs new. worked like a charm.