Why do i keep getting lukewarm air

[king01]

Are you getting reliable heat at the rear vents ? The rear has it's own heater core, and no control valve to interfere with flow, supplying constant hot coolant to the rear.
Is your hot water valve functioning properly ? ( hot water valve modulates front heat only...) . Have an assistant run the selected temperature up and down while you watch the hot water valve to make sure the valve linkage is moving. Or you can select cold temp on the HVAC panel and pull the vacuum tube off the hot water valve and you should see the arm move to the open position and the heater hose aft of the valve get hot.




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Yes, i do get good heat at the back, they get nice and hot like the front. When i flushed my heater core i ended up buying a new heater valve. The old one still works but was just old so would open and close slowly. I had heat for about a week before going on a run 12hr drive and about 2 hrs into my drive i felt a noticeable change that I would only get heat again while accelerating heavy above 3k rpms, otherwise it turned lukewarm.
I feel there is no air in my system as I have tried purging it several times and nothing ever changes, however while accelerating to 3500 then back to idle it does heat up alot just to cool back down.

 

[SlivaRich]

I’ve about had it with this. Have changed my thermostat, coolant is good, purged the system everytime now and unclogged my heater core 2 weeks ago. Was working perfectly fine for about a week before it went bad again. If I accelerate heavy it does heat back up but then goes lukewarm. Is it possible for my heater core to have gotten clogged again?

Are your vent door actuators working properly. openening and closing ? I did all those things that you did to my 03 and finally replaced the 3 actuators (2 in front one in the rear) and once the vent doors were opening and closing properly I was blessed with heat.

 

[Mechatronics]

Interesting discussion and response, Mike. With the first time I've had my EB in colder weather, I'm questioning the effectiveness of my HVAC / heating system. I did try to test the hot water valve as you outlined above, but it basically did nothing. It never moved throughout the test process. I even zip-tied the valve arm, and noticed no discernable difference in heat output at the vents. The cooling system is sound, no leaks, purged, and I've put over 7,500 miles on the new engine since the summer.

It seems like I should be getting warmer air through the vents. Any thoughts?

Just an out of the box idea. Is it possible your water pump is failing and your engine isn't over heating. Would be a rare scenario, but seems possible.