Join Date: Mar 2002
Location: Austin, TX, USA
Usually that is a sign of a bad radiator cap provided you don't have any leaks. Either that or you don't have a termostat installed and the cooling system never gets hot enough to build up pressure.
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI