Car getting real hot....

Heating / Cooling / AC

  1. MAPS

    MAPS FABO Gold Member FABO Gold Member

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    Ok experts

    Here is my dilemma and up here we don't have that many great mopar experts.
    I will try to tell you everything you need to know about the problem.

    Rebuilt 340 six pack, less than 1500 miles, rebuilt last yr, before that I never had heating issues.
    I don't know now if it's the guage but I do feel the car a little hotter than before.
    When I'm driving on the highway non stop the car will reach 160 and stay there but if I start to get stuck in traffic it goes up real fast, if I shut your car off (160) it will go to 180 and higher but when I start moving it will come down a little bit 10 mins bumper traffic it can reach closer 190. 200 it had not overheated ever but I haven't allowed it also as I shut it off.
    If I start to drive just in the city within 10 15 mins @ 25-30 degrees (77 - 86 Fahrenheit) it starts to get hot to 180 and climbing to 200 soon after.

    The rad. Is an after market (Bcool I think,) nice rad I never had these problem before. We changed the thermostat (i think it's a 180, not sure) I have water and antifreeze. It's a 4 speed with 4.10 rear gears.
    The engine is basically. stock aside from a cam (550 lift) solid lifter as well like the cam.
    The shroud I have is very thin came with the rad and like I said I never had these problems, I changed the water temp guage with the rebuilt engine so I'm really confused.
    Is it a water pump, the guage, I changed the belt also.
    May be the cap I've been told,
    Any thoughts? You are the only people that I truly trust with A body mopars... Then I go to the shop and tell them do so and so... So any help will be appreciated.
    Regards,
    MAPS
     
  2. Car Nut

    Car Nut Mopar Master

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    Do you have a Infrared Thermometer Gun that you can verify the temperature when you can pull over. Make sure what your thermostat is rated at. 200 is not that bad in traffic.
     
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    • Tooljunkie

      Tooljunkie King of cobble/master of the broken bolt FABO Gold Member

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      Also, if its 30 degrees c the engine is going to run hot.
      200 is not overheating.
      The infra-red thermometers are cheap, and handy.
       
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      • krazykuda

        krazykuda Well-Known Member FABO Gold Member How-To Section Editor

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        Post a picture of your set up...

        How much does the shroud overlap the fan????
         
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        • MAPS

          MAPS FABO Gold Member FABO Gold Member

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          OK guys I will put some pics up later when I go out to the car.
          The 200° is when I shut it off as it's climbing and I don't want it to go too hot and overflow.

          One other question, What is the max (temp) that I should be pulling over so the car does not overheat. I've been told, 200, 220, 190 ... so this is why I don't wait for it to get hotter than 200° if I'm stuck in traffic I'll shut the car off and wait a little bit like I said, once the car starts to roll it goes down to 180° and soon to 160° and stays there so long as I'm moving but if I get stuck in traffic again, within a few mins it can move up again, real fast.
          It's never over heated but as I said, I don't allow it the time to do so.
          Again thanks to all here that are ever so freaking helpful.
          MAPS

          P.S. THESE ARE THE TIMES I LIKE LIVING IN COLD COUNTRY (CANADA) THE WEATHER KEEPS THE CAR COOL BUT THE SUMMERS GET HOT EVEN BY REGULAR STANDARDS... THESE 85° PLUS DAYS ARE A B^*"H FOR THE CARS...
           
        • toolmanmike

          toolmanmike Moderator Staff Member FABO Gold Member

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          Yep, 200° isn't overheating. If you can't test the cap, get a new one. Cheap fix. You didn't mention what kind of a fan you have?
           
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          • CFD244

            CFD244 FABO Gold Member FABO Gold Member

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            If it has changed, maybe the fan clutch?
             
          • TrailBeast

            TrailBeast AKA Mopars4us on Youtube

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            Everything about this post screams a lack of low speed air flow.
            Curious to see the fan and shroud as well, as these are the two main factors where low speed flow is an issue.
            The radiator is obviously capable, or it wouldn’t cool down when moving.
             
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            • 64mopar

              64mopar Well-Known Member

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              Cap does not effect operating temperature.
              Low air flow at idle/low speeds,coolant moving too fast through the radiator is the problem.
              The temperature will always rise at the sensor when engine is shut down.
              It it is not going above 200,that is not a problem.
              Was the water pump replaced and with what?
               
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              • George Jets

                George Jets 1967 Dart 2 Door FABO Gold Member

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                Here is good trick that I learned from @halifaxhops to get all of the air out of your cooling system.

                Can drill a small 1/8" hole in your thermostat to let the air bleed out of the cooling system. If you have remaining air pockets in your cooling system you are going to have cooling problem.

                20210601_085246.jpg

                The latest 360 build here used the drilled the thermostat, poured in 4 gallons of 50/50 Antifreeze and Distilled Water coolant, it filled right up.

                Fired up the engine on the run stand, broke in the new cam and lifters, let it cool down and the coolant level was still at the very top of the radiator, with the thermostat installed.

                Have had a lot of trouble in the past getting all the air burped out of the 318s on first start ups, not the type of problems I want to have with fresh engines.
                 
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                • Snake

                  Snake Mopar Nut

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                  so how far should the fan be into the shroud ?
                   
                • Dana67Dart

                  Dana67Dart The parts you don't add don't cause you no trouble FABO Gold Member

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                  All engines with a proper cooling system will do the following:
                  1. After the engine is warmed up and at speed (30 to 45 mph or better) the engine temp should be about thermostat temp.
                  2. Slow down in traffic, the temp will rise but at some point it will level out.
                  3. Shut off the engine, the temp will rise, no water flow past the temp probe,
                  4. Start engine again and the temp goes down.

                  Question for all, is 1500 mile's on a rebuild enough to break it in
                  My understanding is a newly rebuilt engine will tend to generate more heat than after it is fully broken in.

                  I have to assume from what you have said the existing rad fan and shroud cooled the same engine properly before the rebuild. Correct?

                  Of the cooling system the only part you replaced was the water pump. Does it have the same number of vains, same length, pitch depth etc?

                  All the above advice is spot on.

                  A quick check would be to let it idel on the driveway, keep monitoring the temp with a know good measuring device. If the temp keeps rising and you get to 220 you have an issue with your cooling system.
                   
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                  • 512Stroker

                    512Stroker We are all here because we are not all there.

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                    No rare at all for a "rebuilt" engine to run a little hotter.
                    Not abnormal for engines to get hot after they are shut off, it is called
                    "heat soaking"
                    Your worst enemy is the 4.10 gear you are running.
                    With 50/50 coolant the system will not boil over unit 230-240*F
                    Drive it
                     
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                    • yellow rose

                      yellow rose Overnight Sensation FABO Gold Member

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                      No, you can’t get the coolant going “too fast” through the radiator. That’s another one of those old wive’s tales that will not die.

                      If the OP has a 180 degree thermostat and it will climb to 200 it has an air flow/coolant flow issue. Like the pump is under driven.

                      The faster the coolant flow the better.
                       
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                      • yellow rose

                        yellow rose Overnight Sensation FABO Gold Member

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                        1-4 is exactly correct. If 1500 miles didn’t break it in, it’s never going to be right. Ring break in should have been done in the first 5-6 minutes after start up.
                         
                      • 67Dart273

                        67Dart273 FABO Gold Member FABO Gold Member

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                        No, but a too low pressure cap or one leaking/ other can allow hot spots to explode into boiling pockets, and encourage unwanted overflow both running, and especially on shutdown
                         
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                        • plumkrazee70

                          plumkrazee70 Well-Known Member

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                          This feels very cut and dry. The temps go to 160 ( too cold in my opinion) while driving. In traffic, it climbs. Sounds like you need a better fan.
                           
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                          • 512Stroker

                            512Stroker We are all here because we are not all there.

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                            What fan are you running?
                            Pic's would really help a lot.
                             
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                            • RustyRatRod

                              RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                              So many people upgrade "things" and never think about the thermostat. The more heat an engine creates, the more quickly it needs to shed hot coolant. Did you use a high flow thermostat? If not, you may be in a position to where you're just not getting the hot coolant out of the engine quick enough.
                               
                              Last edited: Jun 13, 2021
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                              • Snake

                                Snake Mopar Nut

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                                hey Rob, what stat would you say it good.manufacturer.your advice is always right to the point and RIGHT.
                                 
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                                • RustyRatRod

                                  RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                                  I know what ended up working for ME. I used a 160 high flow Stweart thermostat, at @yellow rose's suggestion. I generally don't endorse a 160, but in my situation, running really high cylinder pressure and detonation prone, I did it. Never gets past about the 1/8 way mark on the gauge. I did it trying to cool things down to get rid of detonation issues on pump gas.....and it worked, along with everything else I did. You may not benefit from a 160, but I certainly do recommend a high flow one.
                                   
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                                  • 512Stroker

                                    512Stroker We are all here because we are not all there.

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                                    I currently am using a high flow Milodon 160* stat for4 years now in my 340, seems to perform very well.
                                     
                                  • Snake

                                    Snake Mopar Nut

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                                    Thanks Rob.
                                     
                                  • d1970

                                    d1970 TODAY IS A GOOD DAY TO HAVE A GOOD DAY

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                                    The fan should fit one half of the pitch depth of the blade into the shroud opening. If it is too far rearward out of the shroud air will be pulled from around the blade tips. Being too deep into the shroud can cause turbulence affecting airflow and cooling ability.
                                     
                                  • DustyEd

                                    DustyEd Well-Known Member

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                                    Over a decade ago, I went to the local parts store with my rad. cap pressure tester and it took three brand new caps before I found one that held 16 psi.
                                     
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