6.4 Heater Core Plugged

[jetrinka]

Just seeing how many others have had this problem.

2021 Power Wagon. About 64k on the clock. Noticed this winter the drivers heat was much weaker at idle than the passenger side. Truck fully warmed up. Any added RPM would bring the heat back but as soon as idle hit it would drop drastically. Coolant level fine - both heater hoses nice and hot. Partially plugged core.

I ended up disconnecting the heater hoses where they plug on to the pipes by the passenger bank of the engine. Blew as much coolant out as possible and routed the hoses straight upwards by the cowl. Poured a coolant flush solution in one hose till it came out the other and let it sit for an hour. Reverse flushed with water through a flush spigot. Reconnected hoses and filled back up/bled air. Heater works great again.

Didn't really notice any chunks of anything coming out. The coolant in general still had a good color.

Is this a common thing? Something about the coolant coagulating? Electrolysis and dissimilar metals in the cooling system?

 

[dieselscout80]

There definitely some threads on Ram HDs here and on the web about plugged heater cores and even some on using a coolant filters.

I had mine flushed at some point between 63k and 70k miles and had to replace thermostat at around 85k miles so some coolant was replaced. My plastic coolant recovery tank didn’t look very clean and that’s why I had it flushed.

I wonder if the EGR cooler breaks down the coolant faster.

Some people say it is casting sand that was not cleaned out of the system. I’m not sure I agree with that statement.