I back flush it using air compressor, add water, back fush it more. Back and forth for alomost 2 hours. Noticed alot of rust and particles came out of it. At the end of the flush, both sides are coming out clear.
After bring it of operating temperature. Both hoses (input, output) are hot. I did notice there are "Tees" connections on both sides of the hoses. Is this what you mean by "bypass setup" ?
On the hose closer to the alternator, I took off the connection "before the tee" and connects a 5/8 radiator hose to it. On the battery side, I took off the connection and again fix a 5/8 radiator hose to it with a 5/8 connector.
Will there be a leak on the passenger side if the heater core is blown? So I need to repeat this for several weeks ?