Prof.Dr.Metz

My 99 G.C. is using both antifreeze and oil. There is smoke at idle when sitting for more than a minute or two, not much just noticeable. Could this be head gasket or cracked block? Only when city driving. Just came back from 1500 mile hiway trip with no prob.
Thx

trucker

Smoke after idling for few minutes would indicate valve seals going bad. About the coolant, check for leaks. Check the oil stick for milky oil. What engine?