Heater Core Replaced, Now Blows Cold Air
I had a leaking heater core replaced on my 99 Winnebago with a Freightliner XC chassis. No more leaks, but now the dash heater only blows cold air. I suspect my local truck repair guy (who knows hea...
Forum Discussion
1. IF the Mechanic turned off the engine area water valves--NOT a very smart mechanic. All you do is use needle nose vice grips and crimp BOTH lines at the area of the heater core to prevent leakage and coolant loss
2. DOUBT you have an Air Pocket. I have replaced over 50 Class A heater cores over the years and have NEVER had a Air pocket.
3. Odds are that Green VACUMM line is not opening the water valve, BUT, if so, it will take forever for those water lines to get HOT if there is NO coolant circulating. Put the dash control to HOT and pull the green line. If NO vacumm, that is your problem. Remember, Diesels have a 12 volt Vacumm pump, usually located within 2 feet of the Heater Core box. There will also be a round ball vacumm reservoir close by. You should be able to hear the vacumm pump running as it is loud and vibrates. I will bet the loss of vacumm is the PUMP is not running. The Pump is NOT a Chassis(frtliner) part. It is installed by the OEM RV maker. Doug
2. DOUBT you have an Air Pocket. I have replaced over 50 Class A heater cores over the years and have NEVER had a Air pocket.
3. Odds are that Green VACUMM line is not opening the water valve, BUT, if so, it will take forever for those water lines to get HOT if there is NO coolant circulating. Put the dash control to HOT and pull the green line. If NO vacumm, that is your problem. Remember, Diesels have a 12 volt Vacumm pump, usually located within 2 feet of the Heater Core box. There will also be a round ball vacumm reservoir close by. You should be able to hear the vacumm pump running as it is loud and vibrates. I will bet the loss of vacumm is the PUMP is not running. The Pump is NOT a Chassis(frtliner) part. It is installed by the OEM RV maker. Doug
