cooling system backflush

[bmadd2402]

I know on previous cars (imports) I've had, it was advised against to power-flush your coolant system. but I keep flushing my system ( drain fill run, drain fill run) and cant get all the gunk out. Can I hook up one of those home backflush kits and not damage anything? you know the ones where you hook the waterhose onto the heaterhose? I dont want to sound like an idiot, but the dealers always say not to do it. just wondering if any of you did. and 1 more thing, does anyone have the cooling system capacity? thanks.

[NissanTurboSix]

The only way I know how to flush a heater core is with a hose. I do it all the time at work with no ill effects. Customers cars come in with barely no heat and leave with 140 deg. after a simple flush, air spray, flush, and filll.