I have recently had a new radiator installed in my 2002 jeep liberty along with a new thermostat now my heat only blows luke warm. The thermostat was installed first and the heat work fine but after the radiator was installed is when the heat turned luke warm. Any one with any idea what could be wrong??

When the car is cool, see if the radiator is full. Low fluid can cause luke warm air.

Try reverse flushing the heater core. If this doesn't work, you'll likely have to install a new core. This makes sense, since you had to replace the radiator and the heater core is likely in the same shape. Ensure you are only using a 50/50 mixture of G-05 antifreeze and distilled water.