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Heater problems...hows yours?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by twenty_below0, Nov 9, 2002.

  1. twenty_below0

    twenty_below0 1/2 ton status

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    Location:
    Haines, Alaska ...u.s.
    trying to get hotter air in the K5, things I have done:
    1. New heater core
    2. resealed the box to the firewall & duck work
    3. New hose's & 195 degree thermostat
    4. Supply hose goes from the intake manifold to the supply (top) inlet on the core and return from bottom outlet to the water pump.

    So the question is any suggestions on how to improve the heat, as of now it's hot coming out of the vent's either floor or defrost, but not "REALLY" hot, as in burn your hand after holding it there for 5 minutes.I have felt my buddies Dodge and it get's "REALLY" hot after a few minutes of holding your hand over the vent or your feet.
    I need mine "burn you" hot for the -20 degree weather coming in a month. I can hold my hand back by the console and it's just barely warm so when the temp outside drops it will get worse and thats not good.
    I also had the return going back to the radiator instead of the pump and it was the same maybe a smidge hotter /forums/images/graemlins/confused.gif I thought that going to the pump would keep the hot water circulating all the time and help keep the temp of the heater core higher, thus giving hotter air out of the vents.
    So I'm at a loss, as for the truck it's a 78 with "out" factory air and has manual controls, which seem to be working fine.One concern is that the supply air is all brought in from outside. The intake vent I believe is by the windshield by the wiper arms and from taking everything out when changing the core I cant see that there is a recirculation option on this truck, which would probly help.
    So options I have and or suggestions would be great! /forums/images/graemlins/1zhelp.gif
     
  2. mudhog

    mudhog THEGAME Staff Member Super Moderator

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    mine is burn you hot and i have done nothing to it lol you might try the cardbord in front of the radiator to heat it up during the winter months i have seen many people do that to make it runn hotter /forums/images/graemlins/smile.gif
     
  3. twenty_below0

    twenty_below0 1/2 ton status

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    /forums/images/graemlins/eek.gif I will have to do that but i thought that 195 would be enough for it to be really hot....guess if I knew what i was doing this post wouldn't be here any other suggestions?
     
  4. HarryH3

    HarryH3 1 ton status Author

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    You can block off nearly the whole radiator in the winter. Leave an 8-12 inch diameter hole in the center of the cardboard, so the fan doesn't cavitate. The radiator is designed to keep the engine cool while pulling a 5,000 lb. trailer across Arizona in August ( /forums/images/graemlins/wink.gif ), so you don't need much of it to keep the engine cool during an Alaskan winter! /forums/images/graemlins/shocked.gif

    For a somewhat classier fix, check out www.autoaccessories.com and see if their Lund Winter Cover is available for your vehicle. It fits into your grille and blocks airflow to the radiator. I run it on my wife's Suburban to get heat quicker in the winter. I just leave the lower, center section of the grille open. The rest is blocked off. It does a great job! /forums/images/graemlins/cool.gif
     
  5. twenty_below0

    twenty_below0 1/2 ton status

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    Thx for the link I would like to have one of those covers they are really nice.Still feel like there's something i can do to improve this, someone has to know......is the intake on these years all outside air or does anyone know?
     
  6. Bandit175

    Bandit175 Registered Member

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    Not to insult your intelligence, but how well does your blower work? My heater was pretty wimpy until I got a new blower. You can pick one up for around 20 bucks at your local parts place. /forums/images/graemlins/k5.gif
     
  7. Tweetysuarus

    Tweetysuarus 1/2 ton status

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    $20.00! I paid $10.99 for a new motor at AutoZone!
    Bill
     
  8. gotmud?

    gotmud? 1/2 ton status

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    get one of those aux. heaters that plug into your cig. lighter. not sure if there any good or not though,anybody here have one?
     
  9. big d

    big d 1/2 ton status

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    yep, got two, two different brands, and both suck. they blow air all right, but it never really seems to warm up. maybe yours will be better.
     
  10. HarryH3

    HarryH3 1 ton status Author

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    Since I've never owned one without a/c, I looked in the service manual for a '74. It should be the same as your '78. Looks like there is no option to recirculate the heat. It always draws from the cowl. However, in the full "cold" position, all of the incoming air flows around the heater core and into the truck. In the full "hot" position, all of the incoming air goes through the heater core. At any point in between, air from both circuits is being mixed, based on the position of the temperature control door. Perhpaps your door isn't sealing off all of the incoming air from the "cold" side of the air stream when you have it set to full "hot". Check to make sure that the door is really closing off the cold air properly. /forums/images/graemlins/thumb.gif
     
  11. fortcollinsram

    fortcollinsram 1/2 ton status

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    My heat didn't work worth a poop last winter..turned out the t-stast was stuck open...put a net t-stat in and that baby blows H.O.T. HOT...the other day I went ot denver at 11 at night it was like 20degrees out...I had the heat on with the temp slider to the right but the fan was on low...It was keeping me almost too warm with the windows half-open too...

    Chris
     
  12. MudbogAD

    MudbogAD 1/2 ton status

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    I second HarryH3.
     
  13. twenty_below0

    twenty_below0 1/2 ton status

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    OK, checked the door today and it's sealing best i can tell.I did get an e-mail that said from another guy here on the forum that he had a previous experience with the H20 pump impeller being coroded and keeping the motor cool but not circulating enough to give really hot air....so if someone else will agre maybe i will just buy the high flow pump from Summit and see if it helps.
    NOW has anyone done the switch and noticed a better heater....also how do you guys/gals have your hose's ran to the radiator or pump for the return? /forums/images/graemlins/confused.gif THX
     
  14. 73k5blazer

    73k5blazer Unplug the matrix cable from the back of your head Premium Member

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    You can find a GM Part# 3029730. It's '73-80 something Heavy Duty outer heater box. It allows for a different resistor and most importantly a larger blower motor. You can try to find it at a boneyard, but it's pretty hard to distinguish from the standard one, not to mention it was a pretty rare option.
    Only difference with btw HD heater and stand. heater was this box, the resistor, and the blower motor. No change to the inner heater box.

    Also, I've found that '73-80something inner heater box's (the one under the dash with the core in it) have an auto pass through, that seems to allow alot of the hottest air to escape from there. It's a "vent" if you will that points up to nowhere under your dash on the right side of the box. I've found an '84 box, they don't have this "feature". Goes along with the '73-80's don't have an "off" position for the fan, where the '81-up do. Was considered a feature as it was marketed as "pass thru" ventilation. Apparently they decided it was a crappy thing sometime in the late '70's and eliminated it. Either that or they had a lot of customers complaining they could cook eggs on their dashboard.

    In summary, I improved my heat drastically by installing the HD outer heater case, HD resistor, HD blower motor, and an '84 inner heater box, that I refurbished with seals and a new core, and controls, and my dash doesn't get hot anymore. (My truck is non-ac).

    BlazerMan
     

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