Common Symptom - Insufficient Heat:

Disconnected heater core and added CLR to the core overnight. Back-flushed with garden hose the next day. See results in Lowe's bucket photo. I had a sneaking suspicion that this would only be temporary. The initial heat, just after the heater core flush, was in the 150 degree range, so you couldn't hold your hand next to the panel vent too long. After driving for several days, the heat once again diminished, and I suspect the core is once again plugged with cooling system contamination.

Has anyone had success getting this sand casting contamination out of the cooling system, and if so, what procedure did you use?

Thanks!