I recently did a radiator flush / fill on a 99 s70 AWD. After running clean water through it a few times, I filled it up using by spraying water up through the drain plug in the bottom of the radiator until it started spilling out of the resevoir (with the thermostat open).

Now I get the foggy window and coolant smell with the heater on. I have an extended warrenty but the core is not covered of course.

Could the reverse flush have caused my problems? Any quick checks that I could do before replacing the core? The job sounds like a nightmare, but very fun in a twisted sort of way.

After a little searching, $250 seems to be the going rate for a new Heater Core, has anyone found a good aftermarket core (and yes I saw the post about modifying a Chevy core).