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Water pump/heater fun

Discussion in 'The Garage' started by dyeager535, Jul 9, 2004.

  1. dyeager535

    dyeager535 1 ton status Premium Member

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    On a SBC is the fitting at the top of the water pump supposed to be an "in" or "out"?

    Because of my TPI setup, I ran the heater core "in" line from the water pump. The other hose from the core goes straight to the radiator.

    When driving it the other day in 80* weather, I decided to check heater operation. It wasn't very warm. I checked it on vent setting, and it was colder than normal.

    I've been having problems with the overflow as well...the radiator would be two inches low, but it never seemed to pull any from the overflow...I'd keep adding to the radiator, pop the cap after running it and letting it cool, and the radiator was low again. One thing I noticed while doing this, is that when the engine is running, no coolant is coming out of the heater core line.

    Sounds to me like the water pump fitting is an "in", but I've never dealt with it before.

    I plan on running it from the intake like it should be (well, minus the 180* formed heater hose) but it looks like I will have to get a nipple with smaller pipe threads that what was used on the old intake and in the water pump now. The threads in the intake are the same as the "small" holes in SBC heads (as opposed to the 3/4"? holes in some SBC heads) used for the temp sensor for the gauge.

    Anyone run into the different thread diameter nipple problem either? I was under the impression before that all were the same size, perhaps it's the newer ones that went smaller.

    Just wondering if anyone knows for sure that the water pump fitting is wrong to use. With no coolant flow it's pretty obvious I guess. My dad told me his earlier short water pump has another fitting on the passenger side of the water pump, my later one does not.
     
  2. mrk5

    mrk5 The Sticker Guy Moderator Vendor GMOTM Winner Author

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    If I'm not mistaken, in order to get the radiator to draw off the overflow you need to leave the cap as the truck cools.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    Yeah, I didn't mean to imply it wasn't pulling from the overflow...just had the cap off right after starting to top it off and watch the heater "inlet" to see if fluid was moving, which it wasn't.

    The thermostat isn't very linear in operation either, it acts like perhaps its sticking. We'll see if solving the heater issue fixes that as well. Doesn't overheat, just too much fluctuation in temp, too quickly.
     
  4. 84_Chevy_K10

    84_Chevy_K10 Banned

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    The water pump is an "In" fitting as is the radiator.

    You need to hook one hose to the intake manifold, and the other to your choice of the water pump or the radiator.

    The manifold is the, "out".
     
  5. jones

    jones 1/2 ton status

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    [ QUOTE ]
    Yeah, I didn't mean to imply it wasn't pulling from the overflow...just had the cap off right after starting to top it off and watch the heater "inlet" to see if fluid was moving, which it wasn't.

    The thermostat isn't very linear in operation either, it acts like perhaps its sticking. We'll see if solving the heater issue fixes that as well. Doesn't overheat, just too much fluctuation in temp, too quickly.

    [/ QUOTE ]i'd like to know the answer to this man's problems,also.i'm having the same problem with heater not warming properly.the"in"is to the waterpump,"out"to the radiator with my sunpro temp gauge to the manifold.temp is steady at 195* no matter what the outside temp.it does not fluctuate.in your opinion,would i get the same results from running the "in" to the water neck?is that even possible?
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    Is there a reason you can't run it into the intake like most stock setups?
     

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