Fridge running on propane but not cooling

A fridge that runs (you can hear/smell it working) but doesn't actually get cold is a classic sign of the cooling unit itself failing — ammonia absorption fridges don't really get 'partially' fixed once the cooling unit starts going. Before assuming the worst, check the fridge is actually level (they're picky about this, more than people expect) and that the vents front and back aren't blocked, which can mimic cooling failure. If it's been tilted or off-level for an extended trip, sometimes it recovers after sitting level for 24 hours. How old is the unit and is this the first time this has happened?