Why doesn't my heat work after a radiator replacement and flush?

jimbuntin

I have a 2000 Dodge Ram 2500. I just took the truck to get the radiator replaced and the system flushed. Now my heater will not heat. What could be wrong? The heater worked very well and the heater core is only 2 years old.

jimbuntin

Also, Can stop leak clog your heater core?

Mr_Shiftright

You could have an air blockage from improper bleeding during the addition of the coolant.

You could test for a heater core clog by opening the hood and feeling the input and output hoses to the heater core. If input is hot and output is cold, then you either have a clogged core or a bad heater valve. If neither one is warm, then maybe air blockage or low coolant or sticking thermostat.

jimbuntin

Thanks Mr Shiftright. I actually did kinda massage the intake and output hoses. The were to hot to hang on to for more than a few seconds. I did this to see if the coolant level would drop. It did initially and I added more coolant. Still not heat.

jimbuntin

I should also mention the truck was running at the time.

Mr_Shiftright

So if both hoses are hot to the touch then coolant is flowing through the heater core so....that must mean a malfunctioning blend door or blend door actuator. You can actually scan the HVAC system for codes you know but you need the right type of scan tool.

jimbuntin

Thank you Mr. Shiftright, Is the blend door or actuator in the heater core? Could stop leak play into this issue?

Mr_Shiftright

Seems to me, based on what you've said, that if both inlet and exit hoses are very hot to the touch, then the heater core cannot be plugged. The blend door or the actuator that operates it is like an air diverter. The fan may very well be blowing through the core and directing heat to your passenger compartment, but the blend door could be blocking the flow entirely.

jimbuntin

After doing a bit of research on the blend doors, It looks like the dash has to be removed to access them. I've had a heater core replaced last year, so I know it's a huge cost for labor. Is there anything I can check myself to see if the blend door/s are just stuck. How would these symptoms be caused by a radiator replacement and flush?

Mr_Shiftright

On some cars you can access the blend doors through the glove box. I would suggest either signing up for an online DIY repair service, like Alldata or Mitchell. They aren't very expensive and you get to use them all year for one fee. You want the DIY versions, not the professional versions. Either of these gives step by step procedures, and often good diagrams---but they presume some basic mechanical knowledge and access to some tools.

you can also search through YouTube and you will often (but not always) find someone doing the exact same task as you need to do.

jimbuntin

Update on the issue. I found in the end, the dealership just did not add enough coolant. I ended up adding an entire gallon of coolant over 2 days. Not sure if the new radiator had anything to do with it or not. I think since the system had a flush, there were some air pockets that did not get filled in the system.