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Over heating

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by balazerjake86, Oct 30, 2002.

  1. balazerjake86

    balazerjake86 Registered Member

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    i have a 86 4wd blazer and it keeps overheating (almost 230) i have a new water pump,thermstat,and the heater core is good. I think that i need a new radiator but do not know what i need. i think a three row would be good but i have only seen them for 125.00 is that good or can i find one cheaper somewhere else. also when i look into the radiator i see some stuff on the inside. sorry for the long post but i am a newbie and wanted to give all the info i could.thanks all
     
  2. imiceman44

    imiceman44 1 ton status

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    I would say try flushing the radiator first and see if there is any difference.
    I did mine by buying th kit from wall mart, that kit actually back flushes the whole system including the heater and the engine.
    I think it cost around $20.
    Or you could have your radiator flow tested at a radiator shop and if it's plugged they can clean it for you.
    Unless it's wasted and not repairable I wouldn't change it.
     
  3. Rick

    Rick Registered Member

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    mine used to do the same thing when I was on the highway and it was a clogged radiator. Thats a pretty good price for a 3 row radiator mine was $115 all other places were beetween $160 to $250.
     
  4. balazerjake86

    balazerjake86 Registered Member

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    i did a compression test and they were all within 10 percent. i did buy some flush from walmart but i think it is too clogged. also it only overheats on the interstate. about how much does it cost to get one rodded out.
     
  5. imiceman44

    imiceman44 1 ton status

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    I am talking about the kit not the flush.
    It basically puts a T fitting in the heater return hose, and you connect a garden hose to that.
    After you run the flushing liquid in it, you will run the water from the garden hose and it should thow out any crud the flush loosened up.
    I have no Idea how much it would cost to rod it out, since I do all that myself /forums/images/graemlins/smile.gif
     
  6. TopOff

    TopOff 1/2 ton status

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  7. Muley

    Muley 1/2 ton status

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    If it only over heats on the interstate have you check the fan clutch? My parents burb used to do the same thing, but when you took it out of over-drive the temp atcually went down. Some thing to think about. Replaced the fan clutch and it works like a champ.
     
  8. TorkDSR

    TorkDSR 1/2 ton status

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    wouldnt be the fan clutch, not on the highway. at hiway speeds the fan just wastes horsepower.
    go with the three core rad. make sure to plumb your trans cooling throught it. slap two cheap electric fans on it and never worry about it again

    IMHO,
    Ryan
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    Not to argue, but I've seen another person that said a fan clutch caused overheating problems on the freeway.

    Sounds ot me like there would be an underlying cause if a fan clutch fixes a freeway overheating problem (for all the obvious reasons) but as odd as some problems turn out to be, I'd not entirely rule it out.

    However, if you can see corrosion in the radiator, its more than likely 10 times worse where you CAN'T see it.
     
  10. sosamantx

    sosamantx 1/2 ton status

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    around here $40-45 or so to get the radiator rodded out (if you take it out yourself). i'd call and find out 1st. you could also ask them how much to recore your radiator. a 2 and 3 row radiator should share the same tanks. it could also be a sticking thermostat? anyway, g/l
     
  11. TorkDSR

    TorkDSR 1/2 ton status

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    </font><blockquote><font class="small">In reply to:</font><hr />
    Not to argue, but I've seen another person that said a fan clutch caused overheating problems on the freeway.


    [/ QUOTE ] did he have a guess as too why? ive been racking my brain and cant think of anything /forums/images/graemlins/smirk.gif. at highway speed a fan is basically free rotating, getting pushed by the air more than it is pushing the air.
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    Nope, he had no reasoning. Just that with all the other components replaced (radiator, water pump, heater core, etc.) the fan clutch fixed it.

    I took my fan completely out and drove for two days like that, and its obvious that the fan wasn't needed at ALL when I was moving, as long as I wasn't climbing a hill and lugging the engine a little. The fan obviously was necessary when idling and at low vehicle speeds, but outside of that, it wasn't doing any work.

    So again, I'm not sure why it worked. Of course, it could have been a fluke, like the temp gauge was wrong and started working again, or an air bubble was dislodged at the same time, etc., and the timing was just coincidental.

    Of course, there are the people (on this board even) that have cooling problems, and they only got resolved when the water pump was changed. Tell me how a water pump "doesn't work" yet doesn't weep, and has a tight belt? Pretty unlikely the impeller is slipping on the shaft and not making any noise, right? But if that is the ONLY thing that solved the problem, however unlikely it was, it still fixed it.

    I'd definitely lean towards radiator problems when cruising the freeway and overheating though. I just don't rule things out 100% when I can't physically test them.
     
  13. imiceman44

    imiceman44 1 ton status

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    I agree with you Dorian, but the key here is cruising...
    If they weren't cruising, and they had a bad ass engine with a lean condition, they could overheat /forums/images/graemlins/grin.gif
    I had one experience where I would overheat on highway, and if I let it idle for a couple of minutes it would cool down, my problem was a big fat van with 2.73 gearing, 31"tires and a th350 that made the engine heat up and I had a 4row.
    Well when I seperated the cooling for the tranny, all worked fine.
    My diagnosis though usually is that if you overheat on the highway, you have a clogged or undersized radiator, since the air should be faster than the fan would draw it in.
     
  14. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    mine is running 230 if i drive around the blcok. it has radiator flush kit in now thats why i drive it around the block. my oil pressure is low so a new oil pump should bring the temp down a bit. the radiator being flushed should help a lot as well. and the new headers will help a bit once i put them on. if none of that fizes the problem i will buy a nice 4 core radiator.

    i would double check your oil pressure, it can help a bit.
    and as for the electric fans, a good idea.
    Grant
     
  15. imiceman44

    imiceman44 1 ton status

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    I hope you didn't keep the flushing liquid in for more than 4 hours.
    You are supposed to get it up running then flush it out with clean water then replace with new coolant.
    If you keep it in, it will eat your engine up.
    It is powerfull stuff that will eat through gunk and rust.
    That's unless you are talking about the kit that splices in the heater return line for back flushing.
     
  16. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    its prestone stuff. says to keep it in for a maximum of ten runnin hours no less than three. i can only run the truck for about 15 min at at time if that. i am going to drain it out tomorrow.

    i also got the inline flush kit. i will use that once i drain it of the stuff in it now.
    thanks for looking out for me though.
    grant
     

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