heating Weak heat passenger side

[Pentastarguy]

Some context to my weak and intermittent heat issues on passenger side

Vehicle is a 2011 dodge journey RT (front vents only) 

 

Recently my Journey sprung a leak at the thermostat housing, it was replaced with an aluminum housing and new thermostat, shortly after I noticed a leak while in a stretch where I could not stop as there was no shoulders and had a couple youngsters with me ,the vehicle came close to total over heating, I managed to get some coolant to fill it back up and get it where I needed to. 

 

Upon further inspection I replaced the following as faults were all found in the following 

 

Radiator, Water Pump, new thermostat housing with thermostat, new oil cooler as it was leaking, new rad cap ,everything was replaced the system was vacuum filled and purged of all air,

 

upon testing we were getting excellent heat out of all four front vents, it was pressure tested it held at 16 psi or something for how ever many hours it was left sitting and no leaks and also held vacuum. 

 

I confirmed the doors were opening and closing when changing heat to cold and cycling the vent settings , the only issue  I found on the instrument panel is in climate control when I switch the vents to floor and front vents combo setting it only blows air out of the floor vent, every other vent setting works as it should, floor blows when I set it, front works when I set it, window vent works and window vent floor combo but not the floor and front combo. 

 

The next day the outside temperature dipped to below freezing and all of a sudden I had only heat in the far drivers side vent, the other 3 vents (2 middle) and far passenger vent were all blowing cold, 

 

The following day was well above freezing, so we flushed the the heater core out really good, the water that was pushed through after clearing out the little bit of coolant that was in the core was clean and clear, it was reverse flushed and same result, clean and clear no clogs or signs of sediment or anything and flow was strong in both directions.

 

upon testing I had super strong heat at all four vents, the outside temperature was 5 Celsius at this time. 

 

I drove for approx 25 km and the heat stayed super strong in all four vents, the next day the temperature took a bit of a dip towards freezing, this time my drivers vent was super hot and drivers middle vent was hot, Passenger middle and passenger far vent were stone cold, later that day the temperature went above freezing and the vents all started blowing strong heat again, 

 

The heat also follows the same pattern on the windshield vent setting, hot on drivers and cooler as it moves towards passenger side.

 

Providing the temperature stays above freezing I'm ok, but I live in Alberta Canada so eventually I'm looking at minus 20s and minus 30s coming and if this is any indication of what's gonna happen I'm gonna freeze this winter lol 

 

I feel like I'm missing something obvious, but just can't seem to figure it out.

 

Im trying to keep a pause on tearing everything apart to get at the heater core, as that's a massive job from what I can see,

 

upon flushing there is nice strong flow that comes out in either direction and nice n clear nothing that visually suggests the core is clogged. Next thing I'm trying is flushing out the block and entire system and vacuum filling the system again, but the bill on this on parts and coolant are starting to kill me lol 

 

Any and all advice is greatly appreciated I'm completely stumped on this now. 

 

 

Edited November 30, 2023 by Pentastarguy
Added extra part that was replaced

[2late4u]

check out you tube for the quick and easy way to replace the heater core from the drivers side,,,sounds like you have a blend door problem and there are at least 3 of them checkout YouTube as well on them, since you are getting good heat at times then it has to be the blend doors giving you the problem..good luck and please report back on what you find to be your answer to your problem for others to learn from

[John/Horace]

When the blend door sticks the best indicator is the windshield starts to fog up.  When car is turned off the door defaults to open position to help dump moisture from interior, prevent mould  smell.   You can watch it move when triggered. The blend door is located  behind glove box, it’s around $50 but is awkward to replace.

 

Heater cores seem to get plugged up when oat and hoat coolants are cross mixed. 2011-13 was one type, then it switched.

Heat exchanger is a common wear item, good to get it swapped out.

Edited December 3, 2023 by John/Horace

[thatguy01]

I just replaced the heater core in my 2010.  I did the cut and splice method.  Heat is now Death Valley in all vents.  Prior I had heat only on driver side.  If you search a flush of the heater core may look fine but the passenger side is usually caked up so even though you get 'clean' fluid it's only flushing one half of the unit.  All aside the swap too me about an hour to do.  Quick system bleed and all was good.  My 2010 uses HOAT coolant so I bought Zerex G05 to top off what was removed when changing out.  Be careful and don't mix coolant types.  

 

 

[5rebel9]

YUP, I did my son's 2011 Southern transplant heater core that way{cut&splice} 2 years ago. I've got to replace it AGAIN for the same problem. The car came to us with a heavily "gunked up" cooling system 5 years ago.

With the newer year than yours, there is a little more to remove under the dash due to an airbag mounting, but YES not difficult timewise to do this way. And yes, over that 2 years I have flushed out the core and system at least twice a year!

UNFORTUNATELY this low heat pass. side problem only shows up in colder weather to make repair actions a priority!..... LOL

[yyz]

7 hours ago, 5rebel9 said:

UNFORTUNATELY this low heat pass. side problem only shows up in colder weather to make repair actions a priority!..... LOL

The easiest solution to this is be the driver and wear earplugs!