1. Welcome to Tundras.com!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Tundra discussion topics
    • Transfer over your build thread from a different forum to this one
    • Communicate privately with other Tundra owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

No Heat, no coolant flow through heater core

Discussion in '2.5 Gen Tundras (2014-2021)' started by Devfurnace, Dec 28, 2021.

  1. Dec 28, 2021 at 3:40 PM
    #1
    Devfurnace

    Devfurnace [OP] New Member

    Joined:
    Jun 23, 2020
    Member:
    #48376
    Messages:
    5
    Gender:
    Male
    I have a 2014 Tundra with 129,000 miles. I went to plow the other day and noticed after being in it for a while that it wasn't getting warm. Temp gauge goes up to where I would expect it, replaced the thermostat thinking that could be the culprit. Blew out the heater core hoping to see it was plugged but it flushed out fine and seemed really clean. The weird thing is, feeling different coolant hoses that run throughout the engine bay, they all seem empty and not hot. I would think there would be some at least warm liquid in them. What am I missing. This coolant system has me at my wits end.
     
    Last edited: Dec 28, 2021
  2. Dec 29, 2021 at 7:46 AM
    #2
    blanchard7684

    blanchard7684 New Member

    Joined:
    Nov 18, 2018
    Member:
    #21856
    Messages:
    879
    Gender:
    Male
    check the coolant hoses going into and out of the heater core back on the firewall. Likely that is where you flushed it out.

    If there is a huge temp difference (30,40,50+ degree F) between those hoses and upper radiator hose then the thermostat is suspect.

    On my 2019 I registered between 200-205 degrees at those hoses.

    There are a couple of threads around here from two different folks that have had debris get stuck in the monstrous thermostat housing/manifold. One was a piece of an old radiator cap and the other was debris from...can't recall right now. Lesson learned: large debris can really get wedged into this system and cause you fits trying to diagnose it.
     
  3. Dec 29, 2021 at 7:58 AM
    #3
    Devfurnace

    Devfurnace [OP] New Member

    Joined:
    Jun 23, 2020
    Member:
    #48376
    Messages:
    5
    Gender:
    Male
    I actually changed the thermostat already with an OEM one from Toyota but I didn’t try blowing the lines out or anything. There has to be a huge temp difference from at the hoses at the firewall going into the heater core because one barley gets warm and the other one is very much cold. It has been a nightmare to diagnose.
     
  4. Dec 29, 2021 at 8:41 AM
    #4
    blanchard7684

    blanchard7684 New Member

    Joined:
    Nov 18, 2018
    Member:
    #21856
    Messages:
    879
    Gender:
    Male
  5. Dec 29, 2021 at 1:17 PM
    #5
    Sumo91

    Sumo91 Busy with projects

    Joined:
    Nov 16, 2019
    Member:
    #38726
    Messages:
    1,494
    Gender:
    Male
    TN
    Vehicle:
    2014 MGM Tundra Platinum 4x4
    Bilstein 8112/8100 3.25in lift Dobinson leaf springs 2.1in lift Level8 MK6 wheels Big ole dent in bedside
    Check your radiator cap like @blanchard7684 said, the bottom part falls off and can get stuck in some bad places. Also, these heater cores are a bitch to purge. After I flushed my coolant, my heat didnt work on my driver side, and barely worked on the passenger side. I swapped the hoses around on the heater core and it fixed it and got all the air out, then I swapped the hoses back to normal
     
    mtndds98 likes this.
  6. Dec 29, 2021 at 6:41 PM
    #6
    Devfurnace

    Devfurnace [OP] New Member

    Joined:
    Jun 23, 2020
    Member:
    #48376
    Messages:
    5
    Gender:
    Male
    Well we did a little more trouble shooting tonight. Bought a no spill radiator funnel kit to try and get all the air out of the coolant system. I believe we found a bigger problem. As we were running it with the funnel on and with coolant in it we could see bubbles. They kept coming and coming and coming. Also previous to this I had an issue that if I started my truck after it had been sitting, it would skip cyl 8. Let it run for a minute shut it off, start it back up it would be good to go. Figured it was a coil. Swapped with #6 coil, start it up cold skip again on #8. Decided okay must be plugs. Changed all the plugs. Thought it took care of it. Didn’t drive it much because no heat but while we were running it again with the funnel attached check engine light came on, misfire cyl #8. Read a post and someone said something that made sense to me, possible to have a blown head gasket, might leak some fluid into cyl #8 go to start it up skips but then burns off coolant and runs fine but in turn puts exhaust into the coolant because of a blown head gasket. So I’m thinking that’s my problem. my next thing I think I’m going to try is getting one of the combustion detectors to see if it picks up any exhaust combustion in the coolant and then off to find a mechanic to put a head gasket in for me. Not what I was thinking I was going to end up finding but that’s how it goes. will update as I find more. Or if someone has another suggestion, let me know.
     
  7. Dec 30, 2021 at 7:08 AM
    #7
    blanchard7684

    blanchard7684 New Member

    Joined:
    Nov 18, 2018
    Member:
    #21856
    Messages:
    879
    Gender:
    Male
    There was another thread about a blown headgasket that does mimic your symptoms.

    However in the era of multi-layer steel headgaskets I'm extremely reluctant to believe a headgasket goes at 130k miles unless the previous miles were extremely harsh with poor maintenance and at least one severe overheat situation. Like "Hey I lost a radiator hose in the last 30 miles of the baja 1000 and just went for it" kinda thing.

    That said...

    Combustion detector is a good method to get some further evidence.
    Then look into compression tester.

    A few bubbles in the cooling system isn't a huge deal. If it is larger bubbles and they stay steady then yes it is a concerning sign (of leakage into combustion chamber).

    Either way your heater should still work with a slight headgasket leak.

    Are you having a coolant consumption issue?

    If the reservoir level is going down to the point where you need to add some fluid every 7-10 days then that is another sign.
     
  8. Jan 3, 2022 at 5:02 AM
    #8
    Devfurnace

    Devfurnace [OP] New Member

    Joined:
    Jun 23, 2020
    Member:
    #48376
    Messages:
    5
    Gender:
    Male
    Well unfortunately, it looks like I'm going to be replacing the head gaskets. I went and bought a combustion leak detector and it solidified my worries. It surprises me that with 130K that there is an issue. I didn't think these trucks had head issues. Any other recommendations while I'm in there?

    IMG-4167.jpg IMG-4166.jpg
     
  9. Jan 3, 2022 at 6:32 AM
    #9
    blanchard7684

    blanchard7684 New Member

    Joined:
    Nov 18, 2018
    Member:
    #21856
    Messages:
    879
    Gender:
    Male
    dang. that is disappointing.

    Are you original owner?

    my recommendation at 130k miles and doing a head gasket swap is to address other known weak points.

    Take timing cover off and replace timing set and tensioners. at a minimum the driver's side tensioner. The driver's side tensioner is more prone to failure than passenger side.

    Consider replacing starter. Although not exactly in the realm of engine work, it'd be good to swap it. At 130K miles the starter usually is on the clock.
     
  10. Jan 3, 2022 at 6:37 AM
    #10
    KNABORES

    KNABORES Sarcasm incoming

    Joined:
    Jan 1, 2020
    Member:
    #40572
    Messages:
    8,915
    Gender:
    Male
    Arkansas
    Vehicle:
    2000 Limited TRD AC 4X4 Thunder Grey 270k miles. 2019 Limited TRD CM 4x4 Cement Grey 75k miles
    2000: Bilstein 5100's 16x8 589's with 265/75/16 and 1.25" spacers Flowmaster 50 series over the axle dump Pioneer touchscreen with backup camera Full interior and dash LED conversion Trailer brake controller with 7 pin Bedliner coat bumpers & trim ARE topper 2019: ARE topper with full Bedrug kit and Vortex rack TRD shifter 1.25" wheel spacers (I like to live dangerously) Red tow hooks for that +15 grip bonus
    Not sure I would ditch the factory starter. You could replace the contacts for the starter while you're in there, but reman starters are junk.
     
  11. Feb 6, 2022 at 6:38 AM
    #11
    baraynavab

    baraynavab Toyo Junkie

    Joined:
    Sep 12, 2020
    Member:
    #52130
    Messages:
    369
    Gender:
    Male
    Atlanta
    Vehicle:
    2007 Tundra CrewMax 4x4 5.7L V8
    Hey @Sumo91 I am having the same issue where I do not get any heat from my drivers aide, but my passenger side heat works great. Although I opened up all the Driver side servo stuff thinking my internal vents were not working but that was not the issue. But those servo's worked out to be good and working. That was a headache that I didn't need to go to.. anyways..lol

    Can you please tell me what you did to fix the heat again? not sure why you would swap the heater core lines? How does this get the air out? I am trying to figure out what was your though process here so I can follow the same thinking. Also with this do you think I need to burp the radiator or something?

    BTW I am planning to do a heater core flush to get this issue fixed as well.
     
  12. Feb 6, 2022 at 7:32 AM
    #12
    Sumo91

    Sumo91 Busy with projects

    Joined:
    Nov 16, 2019
    Member:
    #38726
    Messages:
    1,494
    Gender:
    Male
    TN
    Vehicle:
    2014 MGM Tundra Platinum 4x4
    Bilstein 8112/8100 3.25in lift Dobinson leaf springs 2.1in lift Level8 MK6 wheels Big ole dent in bedside

    There are 2 heater hoses going into the firewall, these connect to the heater core, those are what you want to swap around. The heater core can develop air pockets during coolant changes, etc. So if you have a bubble you can't get out, it helps to swap the hoses, it reverses coolant flow, and helps purge any air that may have been trapped and unable to escape.
     

Products Discussed in

To Top