29 Standard 8 Cooling Question in Packard Posted March 17, 2011 Been having a problem with heating up at speed. The coolant wants to foam to the consistency of whipped cream at higher rpms lowering the cooling efficiency. I had the head planed the last time it was off and installed a new head gasket. Haven't had the block magnafluxed since installing new pistons and rings way back in the 1970s or 1980s. Any ideas? Thanks in advance.