the gauges? does ur rad cap get sizzling? cuz to me seems thats the coolant inside the heatercore is just not very hot enuff to offer out heat. so it may be a prob even in ur coolant method, or perhaps anything just like a stuck shut tstat.. Reply http://rv-heater-blowing-cold-ai94938.worldblogged.com/10160352/the-rv-heater-blowing-cold-air-diaries