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2018 ram 2500 6.4 heat issue

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Lb30

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My truck has great heat on passenger side, but Luke warm on driver side, and blows slower on driver side as well. I had it taken to a dealer service center, they ran the diagnostics and said everything was working fine, they only saw a 3 degree difference in temps in both sides. (Which in my opinion, luke warm air is not normal when passenger side will burn your hand if you hold it there long enough). They said it was normal where the core was further away from the driver side vents. They found no issues with blend door, actuators and all of that, even said heater core was fine. I went ahead and back flushed, the core just to see if it had any change, but not much of difference any ideas?
 
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A year later and still same issue and no solution
 
Common issue. Likely a plugged heater core. How’s your oil temp?

I have high oil temps but have bypassed the heater core and temps are still high. I just back flushed both the heater core and oil cooler this weekend, so hopefully something changes.
 
AH64ID said:
Common issue. Likely a plugged heater core. How’s your oil temp?

I have high oil temps but have bypassed the heater core and temps are still high. I just back flushed both the heater core and oil cooler this weekend, so hopefully something changes.
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Oil temp stays around 215 and I’ve back flushed heater core twice and let clr in it for about 30 minutes and still no change
 
Our 2016 Ram PW 6.4L heater puts out luke warm heat at 0F. Wasn't that way until last winter. In Spring of this year I changed the coolant thermostat and actuator door motor due to starting up cold and then coming down our long steep 8 to 10% mountain grade it took a very long time (15 plus miles) to warm up the cab. Thought maybe the thermostat was staying opening or the actuator door was letting in cold air. Didn't fix it, so that's no help to the OP's issue.

I just ordered a Lisle heater core flush tool with the air and water hose attachments. On the firewall there's the inlet and outlet hoses positioned right above each other. Which one of the two is the outlet hose? Upper or lower?
 
both heater hoses are hot, you’d think if the core was stopped up the heater hoses wouldn’t be hot if it wasn’t circulating properly and it’s not over heating. I can hold accelerator about 2500 rpm and I get more heat on driver side but not much more air flow
 
Tis the season for clogged heater core threads. Break out the CLR, vinegar, Fleetguard Restore, Prestone citric acid solution, fish tank pumps, five gallon buckets, meth lab hoses, etc.

Passenger side airflow is across the top of the core. Driver across the lower. If you lack driver heat, it's because the bottom of the core isn't getting coolant flow through it. The passages are blocked/clogged. Only a matter of time before the whole thing is plugged. Crud from the entire cooling system is gathering in the core.

Thanks be to mopar purple and 10 year suggested intervals.
 
johnmyster said:
Tis the season for clogged heater core threads. Break out the CLR, vinegar, Fleetguard Restore, Prestone citric acid solution, fish tank pumps, five gallon buckets, meth lab hoses, etc.

Passenger side airflow is across the top of the core. Driver across the lower. If you lack driver heat, it's because the bottom of the core isn't getting coolant flow through it. The passages are blocked/clogged. Only a matter of time before the whole thing is plugged. Crud from the entire cooling system is gathering in the core.

Thanks be to mopar purple and 10 year suggested intervals.
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I have flushed it twice and used clr in it and whole cooling systems been flushed out and new coolant has been added both heater hoses to core are hot if it was plugged up one would be hot the other would be cold or like warm you would think it acts like a door isn’t allowing the same air flow and heat to the drivers side as the passenger side is
 
Lb30 said:
I have flushed it twice and used clr in it and whole cooling systems been flushed out and new coolant has been added both heater hoses to core are hot if it was plugged up one would be hot the other would be cold or like warm you would think it acts like a door isn’t allowing the same air flow and heat to the drivers side as the passenger side is
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Yes, damper door is the other culprit.

It doesn't take much flow through the top half to make the outlet hose hot. Air doesn't drop the temperature of the coolant much.
 
johnmyster said:
Yes, damper door is the other culprit.

It doesn't take much flow through the top half to make the outlet hose hot. Air doesn't drop the temperature of the coolant much.
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Either way I’m looking at having to pull the whole dash out which is going to be impossible considering I hardly have any time to tear it out and have it put back together and don’t have anything else to drive
 
I back flushed my heater core over 2 days. Reversed the flow a bunch of times. Also user a water air gun to blow crap out. Helped a lot. New thermostat helped more.
 
samsdad02 said:
I back flushed my heater core over 2 days. Reversed the flow a bunch of times. Also user a water air gun to blow crap out. Helped a lot. New thermostat helped more.
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Idk if a thermostat is going to do any good mine already has the 203 rated thermostat engine reaches 210 and never goes any higher than that
 
Lb30 said:
Idk if a thermostat is going to do any good mine already has the 203 rated thermostat engine reaches 210 and never goes any higher than that
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I have a stock 216* rated stat. Even after half hour of driving it ranges from 200*_230*. The old one ranged from 196*-238*.
 
samsdad02 said:
I have a stock 216* rated stat. Even after half hour of driving it ranges from 200*_230*. The old one ranged from 196*-238*.
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Mines factory 203 rated thermostat according to dealer that’s the highest rated one for mine
 
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