My friend is seeing small amounts of white smoke coming from the exhaust. Should I assume that it's a blown head gasket? What else could it be? Can she drive it for another 30 minutes? She drives a DX.

 

it could be ore you could be running rich


WARNING: DONT DO THIS FOR LONG PERIODS OF TIME

you can smell the exhaust and if it smells like antifreeze then yes its a head gasket, but if you have an excessive fuel smell, its running rich, which isnt really a problem, but it should be checked to figure out why its rich. also if its a head gasket look for coolant escaping from the exhaust manifold

 

Plus it would be black if it were running rich. If there's a blue hue it would be burning oil. But since it's just white, it's most likely antifreeze, which might = blown head gasket.