keith g

Recently on my classic 92k impreza Im getting alot of steam/smoke comming through the heating vents whenever I turn my heating on. Up untill this morning it would only do this when the heating was on but now its begining to do it whenever the fan is turned on.
Has anyone else had this problem? I have checked all the water pipes going to the heater matrix etc and they are all fine. I have also checked to see if there was any water left in the system and that is fine to. My only other idea is that it could be an electrical fault which I hope it aint otherwise Im in serious bother
Any help or advice is much appriciated.

Keith.