Luke warm drivers side but hot passenger

[nlambert182]

That is a valid point as well. The sediment isn't just in the core... it's throughout the cooling system.

 

[Tbot191]

So I had tried to bleed the system and there has been no change, I also put a camera inside the system to check the blend doors and everything is operating fine. I'm officially lost as for what to do

 

[voiceguysc47]

If bleeding the system again doesn’t work you should flush out the new heater core. With all the work you’ve done it might have stirred up some junk and blocked the core.

I second this. Had the same problem all winter last year. 3 weeks ago I backflushed the heater core. It spit out a little bit of sediment and the driver's side heat now works perfectly.

 

[Tbot191]

What happens when the AC is running? My belief is that the Driver side is colder than the passenger side.
This is an issue with the TWO blend doors (one for passenger side, one for driver side) One is opening properly, one is not.
Since both sided were hot in the beginning, the ONLY culprit is the blend doors not operating the same. Forget all the Bleeding advice.
Been there.

I put a camera in there to check and I saw everything moving as it should, i bleed the system again for an hour to make sure I got all the air out

 

[nlambert182]

Flush it again. Like mentioned above, there's a good chance more sediment got back into the new core unless you thoroughly flushed the entire cooling system prior to re-install.

Can you give us details specifically on how you tried to bleed the system? What were your specific steps?

 

[Tbot191]

I opened the radiator cap and I put the truck on ramps to have it face up a little I turned the heat on full let it run for an hour while I watched the temp on the digital guage. The temp stayed between 199-209 my vents never changed in temp. Now when I turn the defroster on its just cold no heat on either side but when I switch back to face vents it's hot on one side and kinda warm on drivers side, also when I switch to floor vents it's the same as defroster.

 

[nlambert182]

You still have a clog somewhere.... I would try backflushing the system again...

Those are the exact same symptoms I had. Mine comes out of the shop today from a heater core replacement.

 

[Sherman Bird]

Hello, I have a 2010 2500 5.7. I just replaced the heater core flushed the system before reconnecting the heater core hoses I had hot heat from both sides for about a week now I only have hot heat on the passenger side and it gets Luke warm on the drivers side. I have the single climate control and can't for the life of me figure out what happened.
Does anybody else have this problem? If so did you fix the issue?
Thanks in advance for those who could help me out!

If it worked for a week, and now a change has occurred, logic dictates the the problem is MOST likely an ambulatory one. My vote is on an air pocket in the system. I'm willing to bet, unless you state otherwise, that you did NOT use an airlift device to refill the cooling system after repairs. (Air lift is a misnomer because it uses compressed air to create a vacuum in the empty cooling system, which causes ALL air to be removed.)

Before going all shotgun/fix 10 other things, I'd drain the cooling system, replace the thermostat (if you haven't already) with a FACTORY OE unit, install an airlift adapter, connect the compressed air and let the vacuum build for about 10 minutes, and have my 50/50 mix of coolant in a clean 5 gallon bucket, and let the vacuum do it's job. Even afterwards, and you've run the engine for a few minutes, you'll have to top off the coolant maybe to the tune of 100 ml or so. Good luck! **

** If you already HAVE performed an airlift, feel free to ignore this post and load the parts cannon!

 

[Tbot191]

Ok so here is where in at now, I've tried using an air lift to remove the air pocket from the system. After the vacuum I started the truck and had it running to get to temp, I had a thermometer on the vents to see if there was a change it did seem like I had a little more heat but only through the passengers side the drivers side was about 10° cooler and all I hit was 83° and I still had barely anything through the defrost vent maybe hit 55°. Now also that being said I switched it to floor and face vents I had hot heat on completely on the passenger side and the driver floor vent but not the driver face vent. And now this morning all I had was hot heat on the passenger side. It also seems like when I switch from face vent to defrost the heat just completely shuts off? I'm going to most likely bring it to a shop to do a complete system flush and see what that does.

 

[Tbot191]

Ok, I switched the direction of my hoses and I have heat now, so I'm just assuming like a few people said it was clogged? So I'll be taking it to the shop to get the whole system flushed, after that I'll let y'all know what happens. Thank you everybody who has helped!