Does this sound like a clogged heater core?

[nlambert182]

Check 3way valve more water going to transmission cooler than heater change mine and heat now works fine

I don't think the Cummins has a 3 way valve. My 2 heater hoses go to the EGR cooler and the top of the block. There's no 3 way valve in line with those.

 

[mtnrider]

I don't think the Cummins has a 3 way valve. My 2 heater hoses go to the EGR cooler and the top of the block. There's no 3 way valve in line with those.

You are correct, different design on the cummins than the gas trucks so that doesn't apply to us. It's straight out of the block to the core then back to the riser near the EGR.


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[nlambert182]

That's what I was thinking as well. I've deleted both of my other 2 myself and never recalled having to reroute anything to bypass a 3 way.

 

[oscar1815]

I HAD THE EXACT SAME PROBLEM WITH MY 2016 RAM 2500. I FLUSHED THE HEATER CORE AND IT WOULD BLOW HEAT FOR A LITTLE WHILE THEN QUIT AGAIN. AT TIMES THE PASSENGER SIDE WOULD BLOW HOT AND DRIVER SIDE WAS COLD. I FINALLY ENDED UP SWITCHING THE HOSES AT THE FIREWALL, NOW THE WATER GOES INTO THE HEATER CORE FROM THE BOTTOM AND OUT THE TOP SO THE SAND THAT DIDNT GET WASHED OUT OF THE BLOCK IN PRODUCTION DOESNT FILL IN THE CORES AND BLOCK THE FLOW, ALSO WHEN YOU TURN OFF THE TRUCK THE SAND WILL DROP TO THE BOTTOM OF THE CORE OUT OF THE WAY. I AM SURE THAT IN TIME I WILL HAVE TO REPLACE THE CORE BUT THIS IS THE EASIEST FIX FOR NOW. THE OTHER PROBLEM IS HOW MUCH STUFF IS IN THE BLOCK AND WILL IT PLUG AGAIN IN THE FUTURE EVEN WITH A NEW CORE. HOPE THIS HELPS !!

 

[cKRISgo]

2018 Ram 2500

On my way into work the other morning I turned the heat on for the first time since buying the truck. On my other Rams the heat would melt you within 10 minutes. I noticed that my heat wasn't blowing as hot as my other trucks had all the way into work. The air was downright chilly.

Came home and checked the coolant level and all was fine. The coolant is really clean and looks like it was changed recently. The way this truck was maintained, I don't doubt it. It looks to be the correct coolant as well.

Yesterday afternoon I got the truck to operating temp (it's averaging 190-195 degrees) and then checked the blend door actuators and all were cycling as they should be. I stuck an infrared thermometer on each vent.

Pass window - 123 degrees
Pass center vent - 122 degrees
Driver center vent - 87 degrees
Driver window vent - 86 degrees

I hit both of the heater core hoses with the thermometer and both were reading within 6 degrees of each other.

The only thing I can think of is a partially clogged heater core. I have 2 gallons of the Mopar coolant on the way. What's the success rate of flushing the heater core? I'm going to give it a shot this evening and try to get some heat back to the driver side. Any tips that I need to know before I knock this out? As an aside, I am going to flush with a standard garden hose and if needed I can turn down the regulator on my air compressor and send some lower pressure air through it as well.

Just did ours and a clogged heater core was the problem. Thanks to this site for helping us. Blows hot hot on both sides now.

 

[OutlawTrucker]

I have replaced 2 cores for that very reason. Def heater core stopped up.

 

[Bigles]

Did mine last week ended up being Heater core and checked the Evaporater and it was full of dirt hence I have heard some people complain of a musty smell in there Trucks I changed my heater core and Evaporater and everything is perfect and for those that have a early model truck there is a retrofit kit to install a cabin filter so you don't get the dirt on the Evaporater hope this helps Guys

 

[73-Cudah2]

My 2014 Ram 1500 was warm at best when full heat was set. I took it to a garage for a coolant flush that did back flushing also. That took care if the issue. The problem was the heater core that's why you don't disconnect it. Now it gets so hot I have to back off the heat.

 

[truck2569]

25 miles one way. I let it warm up a bit in the driveway before I left. I was at 120 degrees coolant temp when I left home. It was at 190 within 10 miles. I'm assuming heater core as well. The doors are opening and closing as they should. I believe the heat difference is common with heater core issues from what I've been reading. I think mtnrider is spot on with what I've been seeing.

I'm going to try to slip away from work a little early today and attempt a flush. I did test our Armada heat and it's putting out 150 degrees across all the vents. I would assume that mine should be in that ballpark. I know the others in my sig would melt you to the point that I couldn't run the heat for very long.

I'm not going to have enough time to pick up the air assist gun so I'm going to have to use what I have to try and get this done for now but if I can get the heat back in the cab through this winter I'll work on a more detailed flush in the spring. If it comes to the point of heater core replacement in the future, I'll send it to the shop. I don't have the time or the desire to spend an entire weekend removing my dash.

So my question for you how do you check the blend door on the inside of the housing just above the heater core next to the fire wall. There is a blend door there also. Just curious. That is where my problems were. All the other blend doors were working fine.

 

[nlambert182]

There are 5 blend door actuators that I am aware of.

Defrost/face (driverside)
Foot (driverside)
Left temp actuator (middle behind the radio)
Right temp actuator (middle on the back side of HVAC)
Recirc door actuator (side of the heater box behind the glovebox)

If you are referring to the recirc actuator in the heater box you can see the actuator motor on the side of the cabin filter housing. Remove the cabin filter to see the door.

 

[Dren2500]

I have just joined the forum. Hello all. I have a Ram 2016 2500. 6.4 hemi. 185 k miles. Have replaced heater core 3 times in last 4 years. Really getting old. Started noticing the junk I flushed out of system was what appeared to be rust looking fine particles. I did a lot of checking before posting in this forum, appears to be coming from block. I found that the hemi motors are built in Mexico and some people have said quality control is not the same down there. I believe there is extra casting lines with extra material that is coming loose after time and mileage. Any ideas as to how to seal the inside of block ??? Just thinking outside the box here Need to fix root cause of blockage. Also found out heater core openings are only 1.5 mm compared to opening of radiator which is 3.0 mm. Hence heater core is the sacrificial lamb so to say in this system. I looked into a external filter assembly to the heater core but the system flow and pressures will not sustain a filter and water pump doesn’t have the capability for extra flow rate needed Water pump was replaced along with radiator approximately 20 k miles ago due to being clogged with water pump having sheared shaft HELP !!! I basically have a 3/4 ton paperweight sitting in my garage that my wife will not travel in because of no heat in cab.

 

[Dren2500]

Am I on the correct thread here ??? If not can you direct me which one would be able to help with any suggestions? Thanks

 

[crash68]

Am I on the correct thread here ??? If not can you direct me which one would be able to help with any suggestions? Thanks

I highly doubt there's enough residual casting sand left in the block to plug 3 heater cores and radiator in 4 years with the amount of mileage on the motor. I would suspect other contamination coming from coolant/water used to fill the system. The coolant system uses an OAT coolant, don't mix with any other type of coolant and if your using the OEM, stick with just the OEM. Only use distilled or deionized water to mix coolant with.
People have successfully used coolant filters on the heater cores on these trucks.