I was getting ready to flush (and backflush) the cooling system with the water only (and noticed that some of the radiator tubes appeared to be clogged view through the radiator cap opening. However, the cooling system temperatures have been normal and water seems to be flowing well through the heater core. I would like to chemically clean the cooling system ( with CLR, sulphamic acid, oxalic acid or citric acid) then neutralize with baking soda and flush with water. My concern is that will I be potentially creating a problem ( clogging the oil cooler with loosened particles/flakes that are not dissolved). It seems to me that coolant passages in the oil cooler could get clogged especially since the oil cooler is located at a very low point. If the oil cooler were easier to R/R , I would just remove it . It seems like the the best option would be just to chemically clean the radiator separately and leave the rest of the system alone (water flush only).

Any recommendations ?

 

If you're concerned, then disconnect and plug up the bottom hole of the radiator and clean it separately from the rest of the system.

 

I will do the chemical treatment on each component and flush procedures separately. I still have questions as to whether rust loosened in block will will up clogging the coolant passages in the oil cooler.