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temp. issue on my 350

Discussion in 'The Garage' started by Cornfield creations, Jan 23, 2007.

  1. Cornfield creations

    Cornfield creations 1/2 ton status

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    I just put a new 350 ho in my k-5. The problem I am running into is that when I drive it or even when it warms up fully the temp gauge reads all the way to the red.

    I have tried 3 different thermostats, and 2 different sending units. Both of which are now ac delco. Even though it acted the same with all of them. THe temp still rises.

    I ran it down the road without a thermostat and my gauge read on the first line and never left it. BUt when the thermostat is installed the temp wil go really high and then drop all the way back down to the cold mark.

    Another thing we did was run it with the cap off to get the air out, and also vacuumed out th system. I do not believe there is any more air in the system.

    We put a infared thermometer gun on the side of the block, both sides and the sending unit and at operating temp it always read about 200-220, usually. I never saw it higher than that even though the gague reads it really high.


    I am really at a loss here and I do not know what else it could be other than maybe the wire shorting out or the gauge not working. Even though that doesn't explain why it temp never went up with the thermostat out.

    Any help would be greatly appreciated!!!
     
  2. 86haubs

    86haubs 1/2 ton status

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    What brand and temp. stats are you running. The only think that I could think of is that if they were the same brand and/or temp. Maybe it was a bad batch at the factory.
    Where is the stat from your old engine, try that one and see what happens. Hell it is easy enough, just steal one off your buddies truck real quick.
    If not then it looks like you might have to start chasing wires.
     
  3. Cornfield creations

    Cornfield creations 1/2 ton status

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    The first one was a napa, the second a Carquest, and now I have an ac delco in there. My parts guy at the dealsership said to put the ac delco in there because the parts store brands are nonreliable. So AC delco in installed now.
     
  4. 86haubs

    86haubs 1/2 ton status

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    If you still have the problem, try the old stat? What tempature stats are you running?
     
  5. Cornfield creations

    Cornfield creations 1/2 ton status

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    180, Playing around with the infared I noticed the aluminum intake is about 50 degrees cooler than the block. Would that have any effect?
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    No, especially if your coolant temp is showing that you are indeed heating the coolant up that much. Aluminum will help cool better than iron, but not to an extent that it would matter in this case.

    I'd still be looking at the thermostat, is it installed correctly? Dumb question yes, but highly unusual for three different brands (especially the Delco) to not work correctly brand new.
     
  7. MaxPF

    MaxPF 1/2 ton status

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    Since the IR thermometer reads a normal temp I would suspect the gauge. Do you know anyone who has a good working mechanical temp gauge? Try that. My bet is that it will read a normal operating temp.
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    Since you say the temp actually spikes, I'd use the IR on the thing WHILE it's doing this, if you don't have another gauge to verify off of.

    It would be very odd for ANY faulty portion of that circuit to allow the gauge full sweep, especially going high then dropping back to low. Sticking in one spot would make sense, having full motion of the gauge doesn't. Not only that, but leaving the thermostat out and it staying cold is showing that the gauge is working right at least in the lower temp ranges. Of course, there are plenty of oddities with electrical stuff. I'd never say it's impossible the gauge is at fault. :)

    Then again, no t-stat is supposed to overheat engines because coolant doesn't stay in the radiator long enough.:rolleyes:
     

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