Yesterday I did a CLR flush on a client's truck that had been run with straight water long term. Corrosion was so bad that the thermostat was eaten through and fell into pieces, and all of the smaller coolant fittings were completely closed, causing incurable air lock.
I readied a new water pump to go in with the new thermostat, and performed the CLR flush. It was extraordinarily effective, bringing most of the system back to bare uncontaminated metal.
However, the heaviest rust buildup, behind the thermostat and water pump remained partially intact. I also noticed that these rust deposits were now greenish white in color. When I busted them up using a chisel, they were greenish inside and smelled of CLR. All this after rinsing, performing a baking soda flush, and rinsing again.
My advice to anyone doing a CLR flush would be to give both CLR and baking soda ample time to do their parts, and finish with a good lengthy rinse, so nothing is left in the system.
Also, be prepared to get in there and bust stuff up if the engine is loaded up bad with corrosion.
I readied a new water pump to go in with the new thermostat, and performed the CLR flush. It was extraordinarily effective, bringing most of the system back to bare uncontaminated metal.
However, the heaviest rust buildup, behind the thermostat and water pump remained partially intact. I also noticed that these rust deposits were now greenish white in color. When I busted them up using a chisel, they were greenish inside and smelled of CLR. All this after rinsing, performing a baking soda flush, and rinsing again.
My advice to anyone doing a CLR flush would be to give both CLR and baking soda ample time to do their parts, and finish with a good lengthy rinse, so nothing is left in the system.
Also, be prepared to get in there and bust stuff up if the engine is loaded up bad with corrosion.