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Technical S B C over heats in minutes

Discussion in 'The Hokey Ass Message Board' started by Frames, May 21, 2024.

  1. Frames
    Joined: Apr 24, 2012
    Posts: 5,291


    Ran OK until owner changed from distilled water to 50-50 anti-freeze. Would air locks cause over heating in just a trip around the block? He changed to 160 degree thermostat. Still over heating. Here's a picture of the car at a car show before the overheating. Fan schroud. Ya I know I should have closed up the corners but it did not over heat before. 2023-08-26 14.51.19-2.jpg 2023-08-26 14.51.19-6.jpg Howe custom radiator has worked so good in my hot rods.
    Last edited: May 21, 2024
    AHotRod and dana barlow like this.
  2. Oneball
    Joined: Jul 30, 2023
    Posts: 898


    Is overheating hot on the gauge or spitting water out?

    I’d be looking for air locks too. What thermostat is in there. I had air lock problems with the high flow type. Took me weeks of scratching my head as it tested ok.
  3. Mr48chev
    Joined: Dec 28, 2007
    Posts: 34,229


    I call BS on the "running hot" with a 50/50 mix of anti freeze. It will let it run hotter without puking coolant. Maybe a degree or two but I think too many guys are way too frigging anal about watching a temp gauge waiting for something to be different when they put in antifreeze when the cool guys at the local spit and whittle club say it makes an engine overheat over what their favorite concoction does.
    How hot is "the overheating" 230? 260? or 210? Or 195 when it ran 180 before?

    Did he make any other change on the engine when he added the antifreeze? ANY at all?

    Where is the radiator cap? I don't see one in the photos and how does he fill the radiator and cooling system? I'm inclined to think air lock as Oneball said but if it isn't puking coolant out on the ground it isn't hot.
    I have to bleed air out of the engine on my OT daily next to the thermostat because otherwise that engine will have an air lock. There is no way that you can dribble coolant into that cooling system to get the air out.

    50/50 antifreeze/water will raise the boiling point from 212 at sea level to 223 without a pressure cap. A pressure cap raises the boiling point 3 degrees for each pound of pressure meaning a 15 lb cap raises the boiling point 45 degrees meaning that the boiling point of 50/50 and a 15 lb cap is 268 not that most engines will ever get that high.
  4. 19Eddy30
    Joined: Mar 27, 2011
    Posts: 2,429

    from VA

    Like said above , whats over heating temp?? , pushing water out ,,??
    Install a 180 or 195 stat,
    To get air out up right rad ,
    when you drain down Rad ,
    Before installing stat in intake ,I have slowly fill intake by hand few cups @ time , until full , drop stat in reinstall
    Housing, the top off rad ..I also use the funnel that attaches to the radiator
    That holds around 1qt 1/2 , but empty so when stat opens coolant doesn't run out of radiator, stays in the funnel.
    Or use A Vacuum / fill coolant tool .
    gimpyshotrods likes this.
  5. Check with another temp gauge before you start tearing into things, my 301 SBC takes more than minutes to warm up. JW
    gimpyshotrods likes this.
  6. Budget36
    Joined: Nov 29, 2014
    Posts: 13,529


    I’d have had him take a simple approach if “just changed from distilled water to 50/50 mix “.
    Drain the coolant into some jugs, fill it back with distilled water.
    Then maybe he’ll let you know what else he did…
  7. 34Phil
    Joined: Sep 12, 2016
    Posts: 571


    I had temp sending wire burn on exhaust and ground out, reading hot two miles from home.
    gimpyshotrods and dana barlow like this.
  8. '29 Gizmo
    Joined: Nov 6, 2022
    Posts: 850

    '29 Gizmo
    from UK

    Put water back in and see if it still does it. If it cures the problem you have found the issue, regardless of what anyone says.

    50% antifreez reduces cooling efficiency by 20-30%
    dana barlow likes this.
  9. dana barlow
    Joined: May 30, 2006
    Posts: 5,150

    dana barlow
    from Miami Fla.
    1. Y-blocks

    Still,comes back too=What changed?? ,if it didn't,an now dose? Great looking rod !!:cool:
    Can be simple as,lower hose is sucking closed now,or trem stat sticks,even old frezzplug that was kicked inside block,but not removed/an moved to block some flow. Fan belt started slipping, or if front alum pulley got "V" eat out. Only point being,many little things add up,we some times don't see right away...when hunting the big ones. ;)
    Desoto291Hemi likes this.
  10. :mad::rolleyes:
  11. GearheadsQCE
    Joined: Mar 23, 2011
    Posts: 3,440

    Alliance Vendor

    My guess (and it's strictly a guess) is that he either changed the stat or left it out.
    I had a ot project that overheated from the get go. Brand new thermostat was not opening. Took it back to my parts guy. He said they're running about 50% scrap right now.
    New one fixed it!
    Notice that all the new vehicles run about 210. 180 is old school thinking:D
    MMM1693 and duecesteve like this.
  12. duecesteve
    Joined: Nov 3, 2010
    Posts: 474


    Bad thermostat I think. Take cap off and let run and burps out air
    MMM1693 likes this.
  13. hotrodjack33
    Joined: Aug 19, 2019
    Posts: 4,214


    I ALWAYS drill a couple 3/16" holes in the plate of a new thermostat. Otherwise, when you fill the radiator of a cold engine, the thermostat is closed, and the air in the block CAN NOT escape out of the top of the block.
  14. sunbeam
    Joined: Oct 22, 2010
    Posts: 6,233


    Do you have a mixture of vortec and non vortec parts if so run a bypass hose.
    gimpyshotrods likes this.
  15. dwollam
    Joined: Oct 22, 2012
    Posts: 2,385


    He didn't accidently put the thermostat in backwards did he? That will make 'em hot in a hurry!

  16. Frames
    Joined: Apr 24, 2012
    Posts: 5,291


    A change that he was making. Install an over flow tank. I don't know if that got done. Changed to 50/50 that's when it ran hot. I guess 220. Then he installed the new 160. Same heating problem. I will have him come over tomorrow to read your suggestions and tell him to put the distilled water back in. This is North Carolina. PS; Cap is in the top tank on the back side. A small Howe radiator in my black 27. No thermostat. 2 very small upper hoses. Electric fan because the radiator is so low. Distilled water. Does not run hot. Th GOODSGUYS   PACKARD 016.JPG anks. Lot's of good suggestions.
    Last edited: May 21, 2024
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  17. Glenn Thoreson
    Joined: Aug 13, 2010
    Posts: 1,011

    Glenn Thoreson
    from SW Wyoming

    Thermostat installed upside down? I always drill an 1/8" hole in the rim of the 'stat before installing it. That lets a small amount of coolant flow and helps eliminate steam pockets caused by trapped air in the passages. Coolant level in the radiator should not be full to the top. It will puke a bunch out as it expands from the rising temperature. It will find it's happy spot. I only fill no more than an inch and a half or more below the cap. I have never noticed any difference in temps with antifreeze vs water. But then, I never run straight water, especially in flathead Fords. The thermostats we get now are largely imports of dubious quality and a 160 degree 'stat will often run about 170 degrees on a warm day. Some are no good right out of the box. Heater cores, if you have one, are sometimes great air traps, too. Sometimes I've cured a grouchy air trap by running it without the cap and let it boil a couple of minutes. The steam bubbles in a hot spot will help get the air out. Remember, if it's boiling and steaming, it won't hurt the engine. When it quits boiling and steaming while running, you could have a serious problem including engine damage. So watch it. Never add cold water to a boiling engine. Let it cool first. Good luck...
    Desoto291Hemi likes this.
  18. 3quarter32
    Joined: Dec 10, 2010
    Posts: 514


    Sometimes a160 runs hotter than 180 or even a 185 because once it opens,the water doesn't stay in the radiator long enough to cool. it will stay open on a warm day. Been there.
    hotrodjack33 likes this.
  19. jnaki
    Joined: Jan 1, 2015
    Posts: 9,572


    upload_2024-5-22_2-10-3.png Our 327 powered 1940 Ford Sedan Delivery


    A new radiator cap, new fan belt and new thermostat solved the overheating problem and no more liquid dripping on the concrete floor. In our carport or elsewhere. After months of trouble free driving, our 327 powered sedan delivery started to overheat. so, the first thing was a thermostat change. Ok for several runs to the local surf spot, but then overheating.

    In the same carport, a similar exchange in our trusty 65 El Camino was done, too. We were thinking about selling the 65 El Camino and moving on to the next car purchase. The trusty El Camino had given us 120k miles of trouble free road trips, long vacations all over So Cal and up into the Northern California coastal cruises and as far inland near the tall ridgeline running North/South in Central California.
    So, in our minds, it was listening while sitting in the carport and decided to cause some concern for reliable driving around. No temperature rising until we started our uphill climb on a normally narrow road. By the time we got to our carport, it was bubbling stuff on the concrete floor. So, it was paying us back for even thinking about selling…even after all of those years of trouble free service since new in 1964 fall season.


    We started off with a new thermostat. Then a new upper hose and finally a new cap. Finally, the local mechanic said we probably needed a new water pump, despite not making any noises during operation in normal and long distance driving. So, a new water pump was installed, too. Now, with those items new and replaced, it fired up and another long distance road trip to Baja Mexico was taken. No sense in babying the reliable road warrior. It was ready as usual and no leaks, overheating or problems in coastal Baja roads and cliff area driving.
    5000 miles later and many weeks of So Cal driving, it ran fine. Then, one day, it was an offer I could not refuse, to sell the red El Camino to a local kid from Dana Point. He was going to use is as his surf vehicle and tow a small sailboat behind. The last time I saw it was going down PCH in Laguna Beach and it was painted blue.

    You may ponder over why and try out all of the other choices given. 50/50 antifreeze works most of the time and that is what was used, but yet, still an overheating problem existed in both of our old cars/motors. YRMV

    dana barlow and 26 T Ford RPU like this.
  20. Glenn Thoreson
    Joined: Aug 13, 2010
    Posts: 1,011

    Glenn Thoreson
    from SW Wyoming

    When was the radiator last cleaned? Radiator tubes collect crud and can plug up. This one is rare but does happen: Check to see if the impeller in the water pump has come loose on the shaft. Check the lower hose for softening and if you can squeeze it closed it can collapse and block the flow. The lower hose should have a spring inside that prevents collapse, or a flexible hose with the spring molded into the hose body. You shouldn't be able to squeeze it shut with your hand. An overflow tank is a useful item only if you use a radiator cap designed for use with a closed system. A regular old cap will allow fluid to escape to the tank but it won't pull it back from the tank when it cools and put it back in the radiator where it belongs. A closed system cap has two gaskets. One at the same position as a regular cap and one that seals the top of the filler neck.
    BTW, the post about antifreeze having 20 - 30 percent less cooling ability vs water is news to me. In my 65 years of dealing with such things I have never heard of such a thing, nor have I seen any difference. Where did that bit of scientific misconception come from? There are products on the market that claim to lower the temperature by "wetting" the internal surfaces. Bah! They are pretty wet without that stuff. I have tried that stuff to see if it did anything. The answer is no in my tests. Painting a radiator with paint not designed for such use can raise temps. Heavy coats of paint are a bad thing, too. Special radiator paint applied lightly is needed if you want it painted. Other paints act as an insulator. I prefer no paint at all. But then, I'm just an old grouch... :(
    Last edited: May 22, 2024
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  21. FrozenMerc
    Joined: Sep 4, 2009
    Posts: 3,129


    Boy, there are alot of old wives tales being spread in this thread from people who do not understand basic thermodynamics.

    1. The specific heat content of water (distilled) at 90 C (195 F) is 4.2053 kJ/(kg*C)
    The specific heat content of 50/50 Antifreeze at 90 C (195 F) is 3.688 kJ/(kg*C)
    That is a 13% difference, NOT 20% or 30% as was implied earlier. Specific Heat is the amount of energy (in kilojoules) that it takes to raise one kg of water, one deg C. So yes, an engine and cooling system that maintains 190 deg F with water should run around 215 F with 50/50 antifreeze, all other things being equal. Of course not all things are equal as the coolant temp increases, the difference between the air and coolant temps increases and the rad is then able to reject more heat energy to the air, therefore you will never see a straight 13% increase in coolant temps when switching from water to 50/50.

    2. Thermostats do NOT control the peak temperature the system will reach. Once the thermostat is open, it has NO effect on the operating temperature of the system. Changing from a 180 deg thermostat to a 160 stat, on a system that runs at 210 when at full load will do nothing but ensure that the system is still going to run at 210 at full load. The only thing that will change is the amount of time it takes for the system to reach peak temperature.

    3. The flow rate of coolant through the radiator has NOTHING to do with the amount of heat rejected by said radiator. The amount of heat a radiator can reject from the coolant is defined by the design of the radiator (fin density, materials, size, etc), the temperature difference between the working fluids (air and coolant), and the mass flow rate of the air. By increasing the mass flow rate of coolant through the rad, the temperature difference between the coolant inlet and outlet has to decrease proportionally. I think this is were the confusion occurs. People add a high flow water pump, and notice that the temp difference between the inlet and outlet is now only 5 degs where with the old pump it may have been 10 or 15 degs. Trust the 1st Law of Thermodynamics, and understand that the radiator is still rejecting the same amount of heat, and your engine is still going to run at nearly the same temperature.
    Last edited: May 22, 2024
  22. distributorguy
    Joined: Feb 15, 2013
    Posts: 100

    from MN

    The quickest way to get an engine to overheat is to retard the timing or cause a vacuum leak. Sometimes both happen simultaneously with a bad vac unit on the distributor?
    Sharpone and 26 T Ford RPU like this.
  23. Frames
    Joined: Apr 24, 2012
    Posts: 5,291


    An awful lot of good sugestions. Thanks guys. Got a call from my friend today. His helper set the timing. It was 20 degrees off. He said the acorn nut was tight on the dist hold down clamp. I said. Yes t img018.jpg ight and bottomed out on the too long stud, not tight on the clamp. Put an extra washer on it. Proud PaPa Malcolm at his friends shop. Back when it did not over heat. This is the body that I denoitces.
  24. Frames
    Joined: Apr 24, 2012
    Posts: 5,291


    Timing was the problem. 70 degrees outside this AM. 15 miles to the cruise in. Ran 180 degrees. 160 thermostat. Malcolm stayed with the 50/50 mix.
  25. Dan Timberlake
    Joined: Apr 28, 2010
    Posts: 1,547

    Dan Timberlake

    Glad it's fixed.

    "Malcolm stayed with the 50/50 mix."

    And thus benefits from the valuable and necessary corrosion protection it silently provides with sacrificial chemicals until it is at least 2 - 3 years old.
    427 sleeper and 2OLD2FAST like this.
  26. jaracer
    Joined: Oct 4, 2008
    Posts: 2,503


    Had the magneto slip on my race car one time (small block Chevy). It never overheated, (we ran alcohol which tends to cool the engine) but the headers got cherry red and it was down on power. Because of the red headers, I was sure it was fuel related. One night another racer toled me he had a similar problem and it was timing. I checked and advanced the timing to where it should be and the problem was fixed.
    Desoto291Hemi likes this.
  27. 427 sleeper
    Joined: Mar 8, 2017
    Posts: 2,979

    427 sleeper

    Timing is everything...
    '28phonebooth and Desoto291Hemi like this.
  28. Huh....I was always told it's "Location, location, location!". I learn something new every day.
    427 sleeper likes this.

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