A multi-function heat exchanger for use with a dispensing gun for dispensing hybrid plastisol hot melt material, the heat exchanger having an elongated tubular high temperature heater assembly having a front end hydraulically connected to an inlet port of a dispensing gun and a rear end connected to a heat dissipating assembly which in turn is connected to the outlet end of a supply hose for providing hybrid plastisol material which is liquid at room temperature and under sufficient hydraulic pressure to move the plastisol material through the heat dissipating assembly and the high temperature heater assembly into the dispensing gun when the gun is operated. The heater assembly has a heat source providing sufficient heat to turn the plastisol into a molten liquid as it passes into the dispensing gun. The heat dissipating assembly prevents heat from the high temperature heater assembly from migrating back into the plastisol supply hose.
