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Can water pumps cause problems, or just go bad?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by bigk, Nov 18, 2001.

  1. bigk

    bigk 1/2 ton status

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    My water pump started leaking Friday, so I replaced it yesterday, along with a 180 thermostat and now the guage is staying real steady around 180 or so. Before, I had a 195 thermostat and and the guage would jump around like crazy, and it would overheat occasionally. Can a pump cause problems with cooling or do they just go bad all at once? I never thought it could cause overheating, I figured when they went bad they just started leaking. My brother-in-law said today that the impeller could act up and affect cooling. Anybody else heard of this? If it seems to stay at one temp pretty steadily from now on, I may go back to the 195 on the advice I got from alot of you guys about that being the range these motors are supposed to run in.

    Karl
    Temporarily Unemployed Underwear Model
    87 3/4 ton
     
  2. DesertDueler

    DesertDueler 1/2 ton status

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    If the bearing goes bad it can affect cooling, or if the impeller is roted away it could affect it also. Most of the time when it jumps around like crazy is that it has a leak in the system somewhere.

    86Jimmy 4"&35"MTRs,87 burb 4"&35"MT,69Firebird w/525 hp,and 70GTO live in PHX,AZ<a target="_blank" href=http://www.geocities.com/modifierperformance>My vehicles</a>
     
  3. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Time for a mechanical gauge. They don't bullshit. They just tell you how hot your engine is, right now!!

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  4. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    The pump certainl;y can go bad little by little. You might have also had a bad thermostat?

    <font color=red>GOT MUD???</font color=red>
    My license plate reads:<font color=blue> 8 YR SUV</font color=blue>
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  5. bigk

    bigk 1/2 ton status

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    How tough is a mechanical guage to install?

    Karl
    Temporarily Unemployed Underwear Model
    87 3/4 ton
     
  6. Fierospeeder

    Fierospeeder Banned

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    you could have a bad thermostat that would get stuck.

    74 VW Beetle
    84 Pontiac Fiero
    87 Ford Thunderbird Turbo
    83 Honda Nighthawk 550
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    Sounds to me like the t-stat was bad. Fluctuating temp can easily be caused by a t-stat not "letting go" when it should. (the correct temp) Water pumps, unless the design is different between the old one and the new one, won't affect cooling. The leaking is a bad seal, and the impeller is steel. Don't think you are prone to wear it or the housing out in 150k miles : ) Things such as impeller diameter, whether the impeller is "shielded" (plate used in an attempt to reduce cavitation)and the impeller design itself ("blade" count) will affect cooling ability of the pump.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  8. chevyracing

    chevyracing 1/2 ton status

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    If the water pump was leaking it can cause the system to not pressurize propperly or at all. If that is the case then the temp would flucuate like that.

    John


    Like to go sloppin' 'round in da mud in a rapid fashion....=)

    <a target="_blank" href=http://coloradok5.com/gallery/albun31?&page=1>See my pics here</a>
     
  9. shawnboy

    shawnboy 1/2 ton status

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    A cooler motor is a happy motor. A 165 degree stat works great. Keeps the engine cooler while still maintaining a good heat source. Cooler air is denser air which equals more horse power.
    Shawnboy.

    <font color=red>If you are having too much fun it's probably illegal.</font color=red>
     
  10. chevyracing

    chevyracing 1/2 ton status

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    Shawnboy,
    Horsepower=heat and vice-versa. 180 to 195 is optimum temp for an engine (in most cases).

    John

    Like to go sloppin' 'round in da mud in a rapid fashion....=)

    <a target="_blank" href=http://coloradok5.com/gallery/albun31?&page=1>See my pics here</a>
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    All 3 water pumps (I know its not a ton) that I have had fail did not spew water, and the system would still easily pressurize, and continue to cool the motor. Yes, they typically leak when under pressure, but I've yet to see one leak so bad that it bleeds off all pressure. Heat builds the pressure, and since the engine doesn't stop producing heat until its turned off, it would have to bleed off all the pressure created, all the time. Not saying it can't happen, but even the likelihood of all presure being lost through a dripping weep hole is very small.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  12. chevyracing

    chevyracing 1/2 ton status

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    ok.

    John

    Like to go sloppin' 'round in da mud in a rapid fashion....=)

    <a target="_blank" href=http://coloradok5.com/gallery/albun31?&page=1>See my pics here</a>
     
  13. Fierospeeder

    Fierospeeder Banned

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    running a cooler thermostat on a carbed engine is fine

    the problem with EFI is that the coolent temp sensor is going to tell the ECM that the engine is cold and to increase the fuel mixture. Resulting in poor fuel mileage.

    A way to go around this is to get a performance prom, or buy those programming tools.

    74 VW Beetle
    84 Pontiac Fiero
    87 Ford Thunderbird Turbo
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  14. K10ANDYKHAMNIC

    K10ANDYKHAMNIC 1/2 ton status

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    i have a q , my truck has a 4 core and a mechanical temp guage and it shoots up to like 230 yikes when i turn it off ! wtf ? start it up and it goes right back to 190 ...



    dents ....
    O R D's axles
    NO BREAKAGE :)
     
  15. JIM88K5

    JIM88K5 1/2 ton status

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    The coolant stops circulating, the eng. keeps disapating heat
    &amp; the temp goes up. You start it up and you start circulating
    coolant again.-Jim

    88 5.7 5in lift( I tell my wife it's ten) 35"procomp at's
    700-208-456-3in exh w/flowlowder 10 bolts & some ORD stuff
     
  16. K5 NUTT

    K5 NUTT 1/2 ton status

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    1) If its an TBI engine...stick with the factory 195 stat.
    2) Little known fact...the heater supply line fitting must have an orifice to restrict the flow...if not the heat temp out the ducts will die off at idle...and heat back up at road speed...and w/o the orifice it will raise the operating temps around 10 degree's.
    3) Pressure check the cap with a stant cooling system tool...insure the cap holds rated psi! Every pound of psi = 3 degree's of extra cooling...and run a gm cap...they hold the rated psi where as stants will occasionaly.
    4) Radiator temp drop...best checked with hand held thermo gun or if you don't have one a good DVOM with a temp lead. For proper cooling there MUST be a 10-12 degree drop across the radiator...ie: inlet temp vs. outlet...best checked at hose away from bung as some late model rads have copper inserts in the bungs to prevent the palstic from collapsing. If the temp drop is above 10-12...ie:35...water is passing thru the rad to fast and the water dosen't have the time to cool down....ie: restriction thru tstat.....below 10-12....would indicate its time to pull the rad and send it out to have the core rodded out....50-50 chance of succes.....


    Hope this helps out.

    Azblazer

    1979 K5 350 TBI
    1976 K5 Chalet
    If it ain't got arizona pinstriping.....you ain't wheelin the pee outa her!
     

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