I assume it is probably not advisable to use that radiator Sealant stuff they sell at Auto parts stores, It looks like graphite, supposed to pour it into the expansion tank and as it woks its way thru plugs small leaks in the coolant system. It came to mind as a means to maybe mend my small heater core leak which only gives me a whiff of coolant when i turn the heat blower on but doesn't persist so i figure its rather small.Can hard,unintentional downshifts create so much back pressure that it can blow coolant hoses off if they're already loose?The other day this happened and later that day the top radiator hose popped off, I only link the two incidents because of the infrequency of my missing shifts.There was a good bit of coolant spilled up at the hose neck area and the smelling of the coolant i thought was just excess spillage burning off but its been a few weeks now i'd think whatever spilled should be gone by now yet i still smell coolant when i turn the heat blower on though it does disappear right away.I thought maybe if hard downshifting could have also loosened the hoses on the heater core or forces a squirt ,what I'm smelling from the dash vents is just residue and there really isn't a crack or hole.Probably wishful thinking but if i really don't need to tear the dash apart I'd love to avoid it .The End