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ANOTHER sbc running hot. HELP

Discussion in 'The Hokey Ass Message Board' started by fivefochevy, Aug 9, 2011.

  1. I have a new, not reman, 350 chevy motor. It was running very hot while trying to get it on the road for the nsra nats last week. It had a stock 6 cyl radiator with 2 12inch pusher fans. The timing is set at 8 dgrees before tdc. I switched out the radiator with an aluminum one for a v-8 and put in a new thermostat (180 deg) there is no hood on the car yet. not even a grille. with the rad/t-stat change, it now runs 205-210. it burped maybe a few tablespoons of fluid (distilled water and half gallon of antifreeze). Water pump is moving fluid very well also. I also believe the carb is set good (not rich or lean) any help or other ideas are appreciated. Thanks, Kenny
  2. wildearp
    Joined: Oct 24, 2007
    Posts: 522

    from tucson, az

    Are you sure you have a water pump for the correct flow and not a reverse rotating one?

    Is the aluminum radiator new? Does it have two rows of 1" tubes?

    Are you sure your temp gauge is accurate? Put a thermometer in the radiator to check.
  3. Douglas B.
    Joined: Nov 18, 2008
    Posts: 64

    Douglas B.

    I agree. Here in the good old desert, overheating is something of a daily issue sometimes, until it's sorted out correctly. Do you have a mechanical temp. gauge? If not, you might want to check the gauge. Ever thought of ditching the electric fans and putting on a trusty dusty mechanical fan with a proper fitting shroud? Fan clutch optional. If the motor is BRAND new, it will run hot for the first few miles until everything is seated usually.

    Good Luck!
  4. Runs hot all the time, going 50mph plus, or stop and go?

  5. I have no room to put any fan on front of motor. Rad is Brand new. bad gauge is a distinct possibility. It only threw out a minimal amt of fluid and motor now has 150-160 miles on it. I may switch out waterpump just to see. I may also put a mech temp gauge. it has elec. My gauges are made by Omega , U.S.A. made
  6. It runs hot all the time. usually within a 1/4 mile. morning temp of 75 or mid afternoon in 95 degree heat
    Joined: Jan 1, 2008
    Posts: 1,371

    from Bordertown

    What water pump are you running? short or long? How bout a pic of the front of the engine and your rad and fan set up. I'm sure with a bit more info we can get ya close. x2 on the thermometer or one of those fancy shmancy infared guns....those things are worth their weight in gold.
  8. Russco
    Joined: Nov 27, 2005
    Posts: 4,196

    from Central IL

    A few thing you could check or try. Puller fans would be better than pushers, have you checked total timing not just initial, vac. advance connected to manifold vac source not ported vac source.
  9. long. I do have access to a heat gun. I work for a major U.S. auto manufacturer and one of the engineers offered use of it. That may give me a more narrow list to knock off. I will get pics tomorrow. I am working at the moment.
  10. Willy301
    Joined: Nov 16, 2007
    Posts: 1,426


    Are the shrouds around the pusher fans blocking too much radiator? if they are made together I have seen some that block off quite a bit. Consider upsizing the fans to 2 14"? What brand is your cooling fan? Straight blades or the curved? I have heard the straight blade fans move more air. Just a few high spots I can recall as I am dealing with an overheating Ford small block...
  11. texasred
    Joined: Dec 3, 2008
    Posts: 1,122

    from Houston

    you may have an air pocket in the block. happened with a buddy's new 350 goodwrench motor from chevy, drove us shithouse crazy trying to figure out what was making it overheat..
    Joined: Jan 1, 2008
    Posts: 1,371

    from Bordertown

    ya if you could get the gun, check hoses in and out, check radiator top, center, bottom, left, right and tanks. Hate to say it, but good old short pump, with matching pulleys, bracketry, steel four bladed fan and a nice long as there is nothing mechanically wrong with the engine or radiator you should be golden. "Measure twice water pump once" as that old saying goes.... but also double check the gauge and radiator cap. (Sorry I know its easy for me to say just change to a short pump)
  13. Saxon
    Joined: Aug 9, 2008
    Posts: 2,157

    from MN

    Put a flathead in it. Hey what can I say.
    Joined: Jan 1, 2008
    Posts: 1,371

    from Bordertown

    Try filling it with the front end jacked up off the ground so there is no doubt the radiator cap is the highest point, and u can also try filling it without the t-stat and housing or upper rad hose in place.
  15. v8sammi
    Joined: Aug 6, 2011
    Posts: 12

    from oregon

    Water wetter by red line should help a little
  16. How did you solve that issue?
  17. Have that in there also...
  18. blown240
    Joined: Aug 2, 2005
    Posts: 1,705

    from So-cal

    If you drill a 1/8 hole in you tstat that will allow air to escape from the block to the radiator. I had a straight 6 that was overheating, drilled the hole, and all was fine.
  19. Jason"Clarkie"Clark
    Joined: Jul 25, 2011
    Posts: 6


    You may need to advance the timing a bit,What cam are you running?Your cooling system is very similar to what I am running,except I have an 1800 cfm 15 inch puller on the front of my radiator,with no shroud.and it runs around 180-190 in the 90 degree heat.I would try advancing the timing just to rule it out,you can chase a cooling problem a long way.......
  20. I would be rechecking the timing, if it gets hot that quick. Been there, done that.
  21. I will recheck timing and the 1/8th hole is just a few minutes work for free. I have 2 12 inch fans pushing 1300 cfm total. stock cam too, btw

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