2010 ISX, Have used 4 gallons coolant in 1 week 2300 miles, No external leaks, Head gasket replaced 7 months ago 120,000 miles out of warranty, Seems like antifreeze fumes coming from exhaust into the cab. Could I have another leak in head gasket pushing it into the exhaust? Could their be a blockage in the oil cooler and its not getting enough coolant and boiling it? Also, Having to add oil every 1400 miles so its not going into the crankcase. No its not the egr cooler, its been taken care of, also, after running it for a while and stop at red light can see steam coming from the passengers side of hood. Has anyone experienced this?