Heater core issue

[Ray Ban]

So I've read a couple threads and they don't seem to quite match up with my problem. The heat isn't very hot at all and the other day when I had my ac on it started smelling like burning plastic and I thought I saw a little smoke. So we ran wated through those heater core hoses and it doesn't seem to be clogged.

Anyone have any ideas? Personal experience?

Thanks

[jlevie]

A bad valve comes readily to mind.