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small block chevy water neck and thermostat question

Discussion in 'The Garage' started by 1982blazer, Oct 6, 2010.

  1. 1982blazer

    1982blazer 1/2 ton status

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    Do you have to run a gasket on the water neck on a chevy 350 in order for the thermostat to function properly? Or can you just rtv it. I just put a thermostat in my 79 and down chevy 350 stock intake manifold and stock thermostat housing/waterneck. i put the thermostat in spring down into the manifold. It seems like the thermostat is open all the time.
     
  2. 76zimmer

    76zimmer Flyin Rat Premium Member GMOTM Winner

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    you can run it with RTV, just be careful not to use to much...an 1/8" bead should be sufficient. Check the thermo in a pan of water, immerse it in the pan, then bring to a boil, it should be closed to start, then open as it approaches boiling (212*)
     
  3. 1982blazer

    1982blazer 1/2 ton status

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    I rtved it in there. I was going to biol some water and put it in there before i installed it but i got in a hurry, im thinking about pull it back out tommarow and testing it.
     
  4. 1982blazer

    1982blazer 1/2 ton status

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    There was no thermostat in the truck when i bought it. The thermostat goes in spring side down right im about 98% sure that it does, but i want to make sure i didnt put it in upside down?
     
  5. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

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    yep, spring down.
     
  6. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    I would not use RTV as it can squish out and get in the way of the t-stat working correctly (might be what happened to yours). Also sometimes if anyone has machined the surface of the intake where the t-stat sits then not using a gasket could cause the water neck to break since the t-stat could potentially be sticking above the recessed groove that it is supposed to sit in. Using a gasket would take up any height difference and still seal without breaking the water neck.
     
  7. 70jimmy

    70jimmy 3/4 ton status Premium Member GMOTM Winner

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    There is also an arrow usually on the t-stat to point to radiator. It is fairly common to get a bad t-stat from the store, which is why the boiling water test is smart to do.
     
  8. RootBreaker

    RootBreaker 1/2 ton status Premium Member

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    definitely do it right... buy the $2 gasket and put it in there....

    i have been spending 2.5 years rewiring my riggings (and my last name is riggs so go figure)...
    in addition i am fixing other stuff that i just got by on...

    prime example.. my radiator has a nipple (he said nipple :pimp:) that i just put a rubber plug over with a hose clamp.. did this as i put a 1991 caprice police 350 in... so i went from water pump to heater core to intake

    now i blocked the waterpump and moved that over to the radiator as the rubber cap would disinigrate after 2 or so years due to the antifreeze and heat destroying it...

    do it right from the git go so you dont regret it in the future when you have to spend a massive overhaul to fix everything....
     
  9. K85 Octane

    K85 Octane Tacklin' Fuel Premium Member GMOTM Winner

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    ok, I'll point out the HUGE elephant in the corner

    the truck came with no T-stat?

    o boy
     
  10. 1982blazer

    1982blazer 1/2 ton status

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    Yes there was no tstat in it when i bought the truck, I didnt know it thow.Right after i got the truck home the water pump started leaking out the weep hole.So i replaced the water pump With a remanufactured gm casting long sbc water pump. Then maybe 2 days later the radiator went bad, so i replaced it with a $160 autozone aluminum radiator with plastic tanks. Then i put a high quality made in the usa $11 195 degree T=stat in the truck. My truck seems to be running fine now, Yesterday i drove the truck on a 230 mile round trip with no cooling issues. I bought a cheapish laser thermometer from sears just so i could get an idea of how hot the truck is running. It seems to be consistentley running at about 200-210 thats good enough for me i guess. I dont know why the po was not running a T-stat.
     
  11. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Because many people "think" the truck will run cooler without one when in fact in most cases it will run hot or overheat without either a t-stat or restrictor plate.
     
  12. 1977k5

    1977k5 3/4 ton status Vendor

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    And why would a motor run hotter without a t-stat?


    I certainly advocate the use of thermostats and will always run one but prove said point :deal:
     
  13. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    I've went over this in another thread recently but i'll say it again here.

    The radiator cooling fins are what removes the heat from the system. With the cooling system properly filled with coolant the coolant leaves the radiator through the lower hose and into the engine. Assuming there is no t-stat the water will flow through the engine and out the upper hose and back to the radiator. This is where the problem of no t-stat comes into play. The cooling fins of the radiator cannot absorb the heat from the radiator to dissapate it if the water is continually flowing through it. With a proper system with t-stat in place here is what happens, cold water leaves the radiator through the lower hose and enters the engine where it is heated. There will be no coolant flowing past the t-stat until it reaches operating temp of the t-stat at which time the t-stat will open and allow all of the heater water to enter the radiator through the upper hose and while doing this the cool water in the radiator will enter the engine and once the cool water hits the t-stat it will close. Now the fins of the radiator have the time to absorb the heat and dissapate it as was intended. Once the cool water in the engine reaches the t-stat opperating temp again the cycle will start all over again. i

    It basically boils down to water that is continually flowing doesn't allow the radiator cooling fins to do their job. If you wanted to heat a piece of metal with a torch and kept moving the torch back and forth across the metal it would take MUCH longer to heat the piece over just holding the torch in the place you wanted to heat.
     

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