David Martel wrote:
Wei,

It's possible that you have a small leak somewhere. Such leaks may
not leave water under the truck but will leave a white spot where the
leak is occuring. This is really obvious on black radiator hoses. How
old are the hoses. It may be time to replace them.
If you believe that you have a head gasket leak, take your car to a
mechanic. A leaking head gasket could put water into the oil, which
should be pretty obvious since you are losing gallons of fluid ,or the
leak could be putting water into the combustion chamber where it gets
evaporated and comes out the exhaust.
A good mechanic should be able to diagnose your problem.

Dave M.
Hi,
Yup, old hose is known to collapse causing coolant circulation problem
and over heatoing.