well the gauge stays normal, but if you drive for an hour going over 40 then when you step out of the ar you feel the heat ... when i checked the coolant level about 4 months ago i found there wasnt any so i put some in, i guess that would be a sign that its leaking, the white smoke only comes out at higher rpms so i would think this elimantes the possibility that it could be a head because wouldnt the smoke always be coming out no matter the rpm level ?