  We study in the framework of a constituent quark model the possible
contributions of molecular structures to the XYZ charmonium like states. We
analyze simultaneously the $c\bar{c}$ structures and the possible molecular
components in a formalism which allows us to treat channels below and above
thresholds. The only molecular state found in the $1^{++}$ sector correspond to
the X(3872). Molecular resonances also appear with other quantum numbers. So,
the so called Y(3940) and the X(3915) are suggested to be $J^{PC}=0^{++}$
charmonium states. In the $J^{PC}=1^{--}$ sector we also found significant
contributions of the molecular structures which can affect the phenomenology.
