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Thread: So so heat and lower rad hose not hot

  1. #1

    So so heat and lower rad hose not hot

    Ok so this is interesting. Over the summer I replaced thermostat, both rad hoses, rad, waterpump and t-belt. Didnt notice till today when its like 9F outside, but the heat isnt pushing like it should it seems. Upper rad hose is hot but not so hot I cant hold onto it, lower is cold. I cleared out the cooling system and everything seemed fine this past summer, seemed like no clogs.

    Bad t-stat? Water pump cant possibly be bad, I think I woulda overheated. Temp gauge is about a tick mark off from the middle, so I know its getting hot. Perhaps I have the wrong t-stat? It came with the t-belt kit from ebay from aircabin man (the kit everyone seems to buy) and was a denso/toyota part I recall.

    Clogged heatercore? Bad waterpump, bad or wrong temp t-stat? Or is it just to damn cold? I stuck some cardboard in front of the rad but didnt seem like it did much.

    The truck was fully warmed up just now when I checked all this.

    Edited to add: Just removed the cap, damn coolant isnt even hot!!!!! Coolant didnt fly out either like you normally get..ugh I think the rad is clogged...brand freaking new!!!
    Last edited by CJM; 01-07-2014 at 04:45 PM.
    Marc<br />96&#39; T100 SR5 4x4<br /><br />Other rides:<br />00 Honda 416EX

  2. #2
    Seems like you found your own problem (maybe), but I would also like to add this can be a problem with the valve to the heater core.

    Valve on the firewall of my 4Runner (note: 1" bodylift makes this more accessible, on stock vehicles it sits lower in relation to the engine):


    Close up of the control cable:


    Also with the mixer door on the HVAC box:



    There was a thread a while ago about not giving heat (or not giving cold with the AC). This should help future searches on the topic.




    As for your problem, I don't know any good ways to fix a clogged radiator. Was this one OEM or aftermarket?
    Last edited by Seanz0rz; 01-07-2014 at 04:56 PM.
    2005 Lexus LX470 - Stock for now...

    1998 Toyota 4Runner SR5 V6 4x4 + a bunch of goodies. Lifted, Locked, Illuminated and Armored. Winner,"Best Offroad Truck" - 2010 Pismo Jamboree. It's been upside down and still drives me to work.

  3. #3
    Rad was an aftermarket, but apparently a decent/good brand.

    Im not sure if the rad so much is clogged or if the t-stat is bad, but I think Ill take it apart one day next week (no time this week) and see if I can check and or replace it. If it checks good then I assume the rad is the issue and Ill have to see about getting another one from perhaps a local supplier and not rock auto again.

    I didnt have any issues with cooling/heating via the mixer i think, I have great AC so IDK for sure. This sucks with it being so cold too.
    Last edited by CJM; 01-07-2014 at 05:13 PM.
    Marc<br />96&#39; T100 SR5 4x4<br /><br />Other rides:<br />00 Honda 416EX

  4. #4
    Check the PN on the thermostat and make sure it's not a low temp one, I know that has been an issue in the past.
    2005 Lexus LX470 - Stock for now...

    1998 Toyota 4Runner SR5 V6 4x4 + a bunch of goodies. Lifted, Locked, Illuminated and Armored. Winner,"Best Offroad Truck" - 2010 Pismo Jamboree. It's been upside down and still drives me to work.

  5. #5
    Im gonna go buy one in the next few days and yank it all apart sunday. Hoping the heater core isnt clogged.

    What temp do they spec for? I found in my FSM it said like 183 degrees it opens I think. I checked at 1st toyota parts and apparently there is only one for the 5vz? What is it about 180-190F?
    Marc<br />96&#39; T100 SR5 4x4<br /><br />Other rides:<br />00 Honda 416EX

  6. #6
    We had an issue around here with cars not having much heat after new rads. Turned out the shop that was replacing them (before thay came to the shop where I worked for help) was taking a screwdriver and puching out the center of the thermostat to make sure that everything flowed fine, of course that ruined the t-stat forever.

    Obviously this isnt your case as you installed it yourself. Crack the drain on the radiator, if it seems to drain relatively well, close it back up, and I would suspect t-stat before I went to clogged radiator, since it is new.
    -Chris
    2004 DoubleCab Tacoma PreRunner: 3.4 V6-Auto, DD/Tow Rig
    1997 Lexus LX450: 4.5 I6-Auto, DD
    1984 4Runner: 22R-5 speed, 14 inch bob, 5.29's, lincoln locked rear, lockright front, Armored and Caged by Mossyrocks Fabrication, total disregard for body damage.
    1997 4Runner: GONE
    1996 FZJ80 Land Cruiser: GONE

  7. #7
    I've seen performance t-stats (even TRD I believe) that are 170F and people often complain of no heat.
    2005 Lexus LX470 - Stock for now...

    1998 Toyota 4Runner SR5 V6 4x4 + a bunch of goodies. Lifted, Locked, Illuminated and Armored. Winner,"Best Offroad Truck" - 2010 Pismo Jamboree. It's been upside down and still drives me to work.

  8. #8
    Thanks for the info Chris and Sean! Ill give it a look see next few days, to dang cold right now and no time.
    Marc<br />96&#39; T100 SR5 4x4<br /><br />Other rides:<br />00 Honda 416EX

  9. #9
    Quote Originally Posted by 04 Rocko Taco View Post
    We had an issue around here with cars not having much heat after new rads. Turned out the shop that was replacing them (before thay came to the shop where I worked for help) was taking a screwdriver and puching out the center of the thermostat to make sure that everything flowed fine, of course that ruined the t-stat forever.

    Another popular thing to do is to drill a hole in the flat part so that fluid could pass if the t-stat gets stuck. I guess the idea is that it will slowly overheat and give more of a warning. I had a t-stat on my first truck when I was 16. The thing overheated in a heartbeat. My second truck would have cooling problems and depending on the time of year, length of drive etc I would run no t-stat, high temp or low temp.

    You can also test what you have on the stove. Put some water on with a thermometer in it and wait to see when it pops open.

    Has your coolant level dropped any from when you replaced the radiator?

  10. #10
    Nope coolant level hasnt dropped, I did have a leak problem where I traced it back to one of those stock spring loaded hose clamps was not sealing well. But I fixed that. Honestly thinking about it I didnt have any heat issues till it got REALLY cold these past few days.

    Im wondering if by accident I messed up and bought some premix coolant and threw water in. I always buy the 100% stuff but it is possible. Wonder if got wate rin there and its freezing..which is really bad.. Gonna check it tomorrow in the am.

    I dont think the heater core is bad, no water on the floor at all, no gurgling noises. The truck takes a good 15-20min of idling to warm up.

    This sucks..
    Last edited by CJM; 01-07-2014 at 10:14 PM.
    Marc<br />96&#39; T100 SR5 4x4<br /><br />Other rides:<br />00 Honda 416EX

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