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radiator

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by bigdaddy89, Apr 10, 2001.

  1. bigdaddy89

    bigdaddy89 1/2 ton status

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    I am currently having a problem with my radiator backfilling into the overflow and then the overflow, well overflowing. I was having this problem before and thought is was the radiator so I replaced it with a new one. I also replaced the thermo, overflow tank, and cap. I drained the entire system and used new. It doesn't happen unless I am out wheelin and the temp gets up to about 190-200. I have a 180 thermo in it because I am running a computer chip. The blazer is 1989 w/350fi at/118,000k. Any suggestions what the problem might be?

    GOT ROCKS?
     
  2. muddin4fun

    muddin4fun 3/4 ton status

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    Sounds like bad news! It sounds like there is too much pressure like your getting gas in there. Don't quote me on that. You might see if there is a block sealer you can run and see if that fixes it. I think radiator shops can run a test to see if the head gasket is leaking. Again, don't quote me on that. I've seen a blown headgasket shoot a fountain of antifreeze way up in the air and if the cap is on, it has no where else to go but into the over flo and out from there. that is weird though that it only does that when you're wheeling...

    [​IMG]
    <A target="_blank" HREF=http://k5chevyblazer.homestead.com/home.html>http://k5chevyblazer.homestead.com/home.html</A>
     
  3. Pookster

    Pookster 1/2 ton status

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    I'd get the whole system presure tested. Seems strange though that the back flow is so great. Is it possible that you just... overfilled? (not to sound silly or anything, but I filled up to the hot line when the engine was cold, and low and behold, overflow, overflow)
     
  4. pr1aw

    pr1aw 1/2 ton status

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    Might want to check to see if someone put a reverse flow waterpump in. If there was a groved pully and it got changed out for a serpentine pully this could cause the problem or it could be for marine applications.
     
  5. bigdaddy89

    bigdaddy89 1/2 ton status

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    I just replaced the waterpump about 1 month ago. I was getting the same problem with it backfilling before I replace the radiator and there wasn't much water in the system at the time it happened. I guess I will try to have it pressure checked to see what they can come up with.

    GOT ROCKS?
     
  6. bigdaddy89

    bigdaddy89 1/2 ton status

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    Anymore suggestions?

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  7. 90STYLE

    90STYLE Registered Member

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    I GOT ONE....BURN IT DOWN AND BUY A 90 INSTEAD.
     
  8. bigdaddy89

    bigdaddy89 1/2 ton status

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    90STYLE, Wasn't your blazer broke down at the gas station on the way home the other day? Does it turn right now? Give me a call.


    GOT ROCKS?
     
  9. reddog64

    reddog64 1/2 ton status

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    I got an extra radiator but you already tried that...
    Sorry...

    [​IMG]See me at <A target="_blank" HREF=http://www.inhomenetworking.com/78jimmy.htm>http://www.inhomenetworking.com/78jimmy.htm</A>
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    Ok, ONLY idea I have, and far fetched at that, is to check the overflow tank/hose for blockage. I said far-fetched, but its happened. My sisters Beretta would lose coolant. No leaks, nothing, just would get low on coolant. Of course she wasn't observant. It WOULD leak, but only after sitting long enough to get the water in teh block hot enough to expand enough to get into the overflow.

    Spent an hour or so figuring this out, but some PO had used a radiator sealer in it, and the stuff had basically "come apart" and contaminated the cooling system..looked kind of like puffed rice, only smaller. The coolant would flow into the overflow easily enough, but when the radiator tried to suck it back in, the particles would clog the hose. The water would add up in the overflow, and then would start dumping. Hosed out the overflow, flushed the system, problem never happened again.

    I see you've replaced the overflow tank, maybe just check it and the hose for any blocakge though. Good luck!

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  11. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Only thing I can think of is a bad cap, straight water (boiling at lower temps), bad thermo, blocked cooling system, or cracked head/blown gasket over pressurizing the system. Some of those should be constant regardless of temp or activity (i.e. wheeling). I wonder if temp distortion is causing a crack or gasket leak to open sufficiently to cause the problem only at around 200? Not likely I think, just thinking “out loud”. Sounds like you've already checked/replaced the easy/cheap/obvious possibilities. With a good cap holding back some pressure which in turn raises the boiling point of water, combined with good anti-freeze/boil at the right mixture the boiling point should way over 200 degrees F. I know that is not much help (which is why I didn't chime in earlier) but that’s all I can think of. Good luck.

    Bad Dog

    85 K30 CUCV, 350 TBI, TH400, NP205, D60/C14, 4.56
    Coming soon: 4" lift, 40" tires, massive cutting, shorter wb and rear overhang.
     
  12. bigdaddy89

    bigdaddy89 1/2 ton status

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    I checked to see if I was getting any bubbles in the system to show if I had a bad head gasket, but everything was fine. There was no water in my oil either. I am going to try another cap just to see if maybe I got a bad one. The hose has no had obstructions in it. I just think its not getting pressurized some how, because it shouldn't be reaching the 200 degree mark since I have a 180 thermo in it. I will update when I put the new cap on.

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