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Coolant temp range??

Discussion in 'The Garage' started by BLZN4FN, Aug 14, 2006.

  1. BLZN4FN

    BLZN4FN 1/2 ton status

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    Ok what is the range for coolant temp on a 350?

    reason for this is my father has a 1947 chevy truck we put in a 350 engine
    With 4core radiator high flow pusher fans,195 t-stat and the truck runs at 220-225 all the time. Is this temp ok? I dont see a problem with this temp but he still thinks it should be alot lower in temp what do you all think?
     
  2. 1977k5

    1977k5 3/4 ton status Vendor

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    There should be no problem running at 225 deg, but I would look into upgrading the cooling system. 225 won't hurt the motor, but it is borderline high and if anything goes slightly wrong with the cooling system or you are driving on a particularly hot day (with the AC on?) you will be in trouble.
     
  3. hack500

    hack500 1/2 ton status

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    a pusher pan is not as effective as a puller. can you turn the blades(or reverse polarity) around and mount the fans inside to make 'em pullers?
     
  4. 68MUDSTUD

    68MUDSTUD OCD with shiny things

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    Holy Sh!T!!!! if my truck ran at 225 degrees i would POOP!!! I would shut it down at 210!!!! but thats just me, i am known for doing a whole worst case scenario in my head. wait a second... isnt 220 boiling? thats waaay too hot for me... i like it right at 195-200.
     
  5. Thunder

    Thunder 3/4 ton status

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    Might want to check your temp guage it might be reading wrong. With a 4 core radiator you should be running around the temp your T stat is rated for.. Unless your engine is really pushing some HP.
    Puller fans are more efficient than pusher fans.
    How many CFM are the fans? What kind?
     
  6. 78GMCJIMMY

    78GMCJIMMY 1/2 ton status

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    You may want to try a Lower Temp T-Stat(180 or 165?) ? This may help it run a lil' cooler I believe? Just my 2 cents! Later and GOOD LUCK! 78' Gmc jimmy 350/T-350/np203
     
  7. 1977k5

    1977k5 3/4 ton status Vendor

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    The thermostat only controls the minimum temperature the engine will operate at. It will not solve any overheating issues.
     
  8. 1977k5

    1977k5 3/4 ton status Vendor

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    First, antifreeze makes the boiling point of the coolant higher than 212 deg. Second, the coolant system is under pressure (about 15 psi) and that makes the boiling point of the coolant significantly higher (about 250 deg fahreheit for just water, higher for 50/50 mix coolant). Some aluminum engines are sensitive to high temps but iron SBC's are pretty damn tough when it comes to high temperatures :D
     
  9. HarryH3

    HarryH3 1 ton status Author

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    First make sure that the gauge is correct. If it is, then 225 is too hot.

    You could have a bad thermostat also. I noticed the temp slowly creeping up over the last week or so on our '94 Suburban. It usually sits right at 190-200, even with both a/c units blasting, in 100+ degree heat. Then it started running at 210, then creeped up to 220. I dropped in a new 195 degree thermostat and the temps dropped right back to 190-200. I guess that the spring in the old thermostat was slowly failing. :(
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    If it's consistent at that range, I'd probably suspect the gauge. I've yet to see a bad radiator, insufficient fan cooling, bad pump, or bad thermostat result in any consistent temperature, especially something in the "safe" zone.

    GM ran theengines up to 220* before the fans even came on, so it's not goig to be unsafe. But personally, big temp swings aren't a good thing, and as mentioned, a cooling system in proper shape should run right near the t-stat rated temp, and a cooler t-stat will not fix an overheating problem.
     
  11. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Something that nobody has mentioned is do you have the proper water pump installed? If you are running V-belts you need a standard rotation water pump but if you're running serp-belt you need a reverse rotation water pump. Using the wrong pump will definately make it run hot.
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    I always hear the warnings about the reverse rotation water pumps, have you or anyone ever seen what results from doing so?

    I've not myself, so I'm curious. I'd think it would be near catastrophic in regards to engine temp.?
     
  13. obijuan

    obijuan 1/2 ton status GMOTM Winner

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    also the timing can make it run hotter but im not sure if it could go to 220. mine normally runs at 185-190. every truck ive had sat there very consistently with and without a thermostat
     
  14. BLZN4FN

    BLZN4FN 1/2 ton status

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    Thanks all For the input.

    The truck runs 220 all day long in hot AZ weather only time it hits 225 is when my dad is hard on the little pedal.

    The waterpump is new The 4-core is 1 year old he is running a 195 t-state
    I wish he had a puller fan but there is no room between the engine and the radiator. So only option is a pusher fan:crazy:

    Joys of putting a 350 in place of a inline 6 where the truck never had a small block option.
     
  15. Cricket

    Cricket 3/4 ton status

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    Bo can't you just drop in a 180 stat?
     
  16. ntsqd

    ntsqd 1/2 ton status

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    Not a reverse rotation, but one of those "Flowcooler Unidirectional" pumps. Engine ran warm no matter what other mods were made. Dumped it and put on a pump intended for the application and the temp dropped as if by magic.
    I suppose you could extrapolate that to what you might expect from the wrong rotation pump, but I don't know how reliable that forecast would be.


    I kind of doubted that above statement about Anti-Freeze raising the boiling point of water so I went looking to see what I could learn. I've not yet found a definitive answer to that particular question, but what I have found makes it a moot point.
    From: http://www.racerpartswholesale.com/redtech3.htm
    "Water has amazingly superior heat transfer properties compared to virtually any other liquid cooling medium - far superior to glycol-based coolants."
    From: http://www.stewartcomponents.com/tech_tips/Tech_Tips_4.htm
    "UNEQUIVOCALLY WATER IS THE BEST COOLANT! We recommend using a corrosion inhibitor comparable to Prestone Super Anti-Rust when using pure water. If freezing is a concern, use the minimum amount of antifreeze required for your climate."
    From: http://www.stewartcomponents.com/Stewart_faq.htm
    "Q6. What is the best coolant to use?
    A6. If freezing is not a concern we recommend water with a corrosion inhibitor. If freezing is a concern, use the proper amount of antifreeze required for your climate."
    From: http://www.stewartcomponents.com/tech_tips/Tech_Tips_6.htm
    "1 BTU is the amount of energy required to raise 1 pound of water 1°F. Of all common liquids water requires the most energy to accomplish this. Therefore water has a specific heat of 1°. An Ethylene Glycol/water mix has a specific heat of .5, meaning it requires only .5 BTUs to raise the temperature of 1 pound Ethylene Glycol/water mix 1° F."

    Based on this I think it reasonable to assume that even if adding Anti-Freeze to the coolant does raise the boiling point that the side effects aren't worth it.
     
  17. blazeonchevy

    blazeonchevy 1/2 ton status

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    when i first started driving my truck on the street i looked down at the thermostat and it was reading 230:eek1:... so i pulled off and let it cool. but it would never boil over. so i cleaned out the radiator(sprayed it with a hose) and got all the mud out. but it still did the same. so i put in an aftermarket thermostat and according to that its running right at 200 im thinkin the stock gauge was off since it never would boil over or loose any water for that matter. so check the gauge some how?:confused: ?.... or try a new thermostat i know they can go bad....other than that i am no help. sorry..:o
     
  18. dyeager535

    dyeager535 1 ton status Premium Member

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    Antifreeze boiling point is rated at 15PSI, so whatever you see on the bottle is already going from the 248* (or whatever it is) boiling point of water alone at 15PSI. I spent a bunch of time looking that up awhile back, I believe if you look at the bottle, (or online) the manufacturer states which test is used to make their claims, and it's a test that uses pressurized coolant.

    IMO you should never be relying on antifreeze for boilover protection. If you are over 240*, you already have a serious problem and even 25* more before boiling isn't going to help you.

    Antifreeze is needed for *freeze* protection and for the additive package. If it hurts heat transfer (which it does) then why would you want to run any more than necessary?
     
  19. 1977k5

    1977k5 3/4 ton status Vendor

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    ^^^^Agreed^^^^^
     
  20. nemesis_pyros

    nemesis_pyros 1/2 ton status

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    Try putting a 454 in there. Its great fun to drive but with a 3 core high flow rad and a high flow water pump it still gets up to 210 in stop and go traffic. As soon as i'm moving she cools right back down to 160. I'm thinking the flex fan just isn't enough so I'll be putting an electric pusher fan to help. I do have a question for you. You Say that the 350 is in there too tight to put a fan between the engine and the rad. I have about 4 inches with the big block and it puts my fan about an inch or so from the rad. We did move the rad forward a bit(very easy to do) that probably gave us an inch or so more room. If you ever need help figuring something out on these trucks drop me a pm. I've had my '49 completely apart and ran into what seems like every possible problem.
     

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