Car getting real hot....

Heating / Cooling / AC

  1. 512Stroker

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

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    Partner you may think that the engine is the same as it was before you rebuilt it, but the fact is appears you replaced the majority of the major components.
    Heads, cam & lifters, crankshaft and related parts I dont know if you had any machining done to the block, hell, just changing the heads and head gaskets could/will alter your original C/R having a dramatic effect on cooling.
    You just did not do a Dupont rebuild of your engine you changed it alot.
    I'm not surprised that it performs differently.
     
  2. IfItsGotWheels

    IfItsGotWheels X S Tech

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    I wouldn't be too concerned about 200-205 degrees. With your rad cap & antifreeze in the motor you should be able to see 210-215 safely without blowing the cap. Back in the eighties I had a 13-1 340 & it ran all day at 180 to 210 degrees.
    Don't forget that antifreeze not only stops your motor from freezing but also raises the boiling temp of your coolant.
    Montreal stop & go summer traffic is brutal (hot & humid) My guess as to why your pre-rebuild motor did not overheat is that it was tired & probably didn't have much compression left to build heat.
    As others have said, ditch the next to useless flex fan & that restrictive shroud & you'll see an instant improvement
     
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    • 1969383S

      1969383S FABO Gold Member FABO Gold Member

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      Don't guess and think for a second or two.
      You changed things and now have issues. Never mind the car aged a minute amount.

      Did you use all the same gaskets as before? What else got changed. Do the rewind in your head and do not get reactionary at this point, it usually makes it worse and more expensive! Did timing change or does it need too with the new cam and such! Assume you checked those basic items.
       
      Last edited: Jun 16, 2021
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      • Snake

        Snake Mopar Nut

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        the very last pic
         
      • RustyRatRod

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

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        That's the MP viscous fan, so yeah it's worth something. They sold for around 150 new, but they've not been available for years. Mancini "says" theirs is the "viscous fan package" and it is a viscous fan package, but it's not the good staggered blade fan. I'd take 150 for mine. Otherwise, it can rust on the shelf. lol So there's that.
         
      • Dale Davies

        Dale Davies Well-Known Member

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        Yellow rose, actually you can have too fast flow threw the radiator. A/C equiped cars had a water pump with fewer vanes on the impeller to slow the flow through the radiator for more temperature exchange to prevent overheating in traffic.
        The rad cap has nothing to do with temperature as long as it is not letting coolant out.
        I would be looking at the fan and fan speed. Is the fan an electric with the radiator? Those need a 40A relay and 8ga wires from the battery, through a 40A fuse, through the relay and to the fan. A temp switch rated at 190° in the bottom tank will control the relay. Remember it needs an equal ground for the fan.
        If the fan is on the WP, does it have 5 plus blades and it should be centered front/back in the shroud.
        You could also try the A/C WP.
         
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        • yellow rose

          yellow rose Overnight Sensation FABO Gold Member

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          No, you can’t move the coolant too fast through a radiator. That is wrong. Think about what yo are saying and what you want me to believe.

          You are saying use less flow so the coolant stays on the radiator longer. So I’ll ask you. What happens when the coolant spends more time in the radiator???? The coolant in the block and heads spends an equally longer time picking up heat. So you gain nothing and lose the ability to keep the coolant temperature closer to the thermostat opening point.

          It’s really that simple. If the coolant coming out of the engine is staying there long enough to leave at say...210ish, and the system is capable of a 20 degree temperature reduction then the best you can hope for is a 190 degree coolant temp. Doesn’t matter if you have 190 thermostat or a 160 degree thermostat.

          If you speed up the coolant so it doesn’t stay in the engine as long and the coolant is now leaving the engine at say...195 then you can reasonable expect to keep the coolant right at the 190 degree thermostat opening.

          So we can keep going. What if we can keep the coolant coming out of the block at 180 because it doesn’t stay in there so long? That would mean you could reasonably expect that with a 160 degree thermostat you would be right at thermostat opening. Maybe not on a 105 degree day, but certainly when ambient temperatures aren’t hotter than the hubs of hell.

          With my cooling system, I run a 160 degree Stewart Components high flow thermostat and on 100 plus degree days it will run at 160. All day long. If I get stopped by a long train it might, maybe might climb to 170 or a skosh more. I’ve never seen it hit 180.

          That’s one reason why you don’t slow the coolant down. Overdrive the pump as fast as you can find pulleys and to the limits of keeping the belts on and the fan blades on the fan.
           
          Last edited: Jun 16, 2021
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          • RustyRatRod

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

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            You just described my cooling system to a tee right here.
             
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            • MAPS

              MAPS FABO Gold Member FABO Gold Member

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              512Stroker

              Oh I agree with you 100%, reason I wrote what I did is (Can't recall the name now) is someone asked if I had rebuilt the engine or thought it was a rebuilt and maybe I just had the gaskets or some seals changed so I explained it was a rebuilt, completely. Aside from the pistons, everything else was changed, from the head gaskets to the seals and everything in between were changed over, I just can't understand why it now rises up so fast. That's all.

              As for the mechanics to the car, I'm no expert, like I said, I have to rely on the mechanic that I have and although he is a great mechanic, I just think he is not too invested in mopars.
              They have a few cars running 9s.on the street and about 10 yrs ago won that Street outlaw they had in Toronto with a mopar running high 8s but overall it's a Ford Chevy place and that's where they are at ....the mopars are second fiddle.
              Believe me when I say it is hard to find a good Mopar mechanic up here (aside from one they call Greedy) so I'm always getting the best info here and just having them do it to the best of their ability now.
              Even my six pack that lately had some issues has brought me to the point of just swapping for a 4 barrel and bypassing the headaches of hearing, remove it, mopar crap, etc.. but I like it and it's still on.
              I just thought maybe my water pump may have given out ? I'm going to go ahead and order a 7 blade fan from the same radiator company and change the cap for now, see if that helps.
              After that I'll go with the shroud.
              I feel this shroud is as complex as the Shroud of Turin. Is it, is it not. In the end seems only Jesus knows the true answer of the shroud problem.

              Thanks guys.
              MAPS
               
            • Tooljunkie

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

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              You ever notice,changing water pump pulley to a smaller one not only speeds up water pump, it speeds fan up too. When i was on the hunt for a pulley for my 360,i found 3 and chose the smallest. That one is going to need all the help it can get.
               
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              • Mattax

                Mattax Just the facts, ma'am FABO Gold Member

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                This is correct.
                Additionally the pressure cap also raises the boiling point. Once the coolant boils, that's when control of the heat transfer is lost.

                Normal (stock) coolant temperatures are roughly middle of the gage (180). A little more than middle is not a problem. The thermostat helps insure the engine gets up to the intended minumum temperature. Under normal driving conditions, oil temperatures will be similar to the coolant temperature. Getting the oil hot is very helpful getting rid of moisture that has condensed in the engine.

                Lets look at the original expected coolant temps.
                1966 Dodge Dart Coronet FSM
                upload_2021-6-17_10-36-4.png

                1970 Plymouth FSM

                ' upload_2021-6-17_10-31-7.png

                Notice with the earlier cars, 175 degrees is the minimum where the radiator is allowed to begin to aid in cooling. Further that full flow to the radiator is not expected until the temperature gets up to 200 degrees.

                With the later cars using 190 and 195 degree thermostats full flow doesn't take place until 210 and 215 F.

                Another point of reference can be had from smogged vehicles equiped with coolant temperature overide switches. For example the HD CTO used by AMC Jeep to head off overheating at idling with A/C running on a hot day kicks in when the coolant hits 220 F.

                If someone wants to run their engine cooler, that's fine.
                My point here is that coolant temps in the range being discussed, 190 F to 210 F, are not by themselves an indication of a problem.
                 
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                • Dartswinger70

                  Dartswinger70 Only thing I ever bought new was a Fender Strat

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                  During the rebuild was the block water jackets cleaned out real good?
                   
                • Dale Davies

                  Dale Davies Well-Known Member

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                  Go argue with the Chrysler engineers. This was their information in the day. Slower in the block allows more heat transfer to the coolant and then more reat transfered to the air in the radiator. Your results may differ, but the old Chrysler engineers were pretty fart smellers.
                  Since posting previously, I have seen the photos of the fan and shroud. The fan is pulling air partly from the engine compartment and thus loosing draw through the radiator. The fan could be spaced ahead, but you do not want to get too close to the core. More work is involved, but a better solution is to space the shroud back. It would also be advantageous to roll the inside diameter about 45° on a 1/2" radius, in the direction of flow.
                   
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                  • Dartswinger70

                    Dartswinger70 Only thing I ever bought new was a Fender Strat

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                    The infrared thermometer is a good idea but the car will tell you if it is hot.is it pinging? does it "diesel" when you shut it off? etc. Im sure this has all been said but yeah the cheap stuff, a coolant flush is there sludge in the block and radiator?, then thermostat, then cap then shroud..after that I'd be suspecting the water pump itself, sometimes they go bad and you wont know unless you pull it. Only so much it can be really. OP you said it stays cool going down the road ,have you considered 'electric fans"?
                     
                  • ir3333

                    ir3333 Well-Known Member

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                    well i've had a few cooling problems and a hi quality rad always solved my problems...(read not a $300
                    rad!)
                    Tuning and a fan that moves a lot of air are also required. Shrouds and clutch fans not so much
                     
                  • 512Stroker

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

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                    Results will differ I am jamming the coolant as fast as it can thru my iron head 340 with a Griffin 2 core radiator and an 18 inch 7 blade clutch fan, factory shroud and Milodon 160* stat. Car rarely gets above 160* with the A/C on it hovers around 180*.
                     
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                    • Mattax

                      Mattax Just the facts, ma'am FABO Gold Member

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                      A/C water pumps were driven faster than non-a/c water pumps.
                      35% faster in 1968
                      The faster they are spun, the more liquid flows and the likelyhood for cavitation increases. Those are both minimized with the smaller impeller.
                      upload_2021-6-14_17-7-58-png.png

                      Ignore the yellow markup. That was for someone else's question.
                      The big issue with A/C is not the additional load on the engine, which is real, but only a significant load percentagewise at idle rpms.
                      The big issue with A/C is the heat exchange with the air - the same air that goes through the radiator. Its critical to keep enough volume of air moving at idle and low speeds.
                       
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                      • Dale Davies

                        Dale Davies Well-Known Member

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                        Balance is also a factor. 3 of the blades are more evenly spaced and then the two are closer together. Balance and noise. The 5 blade are definately quieter.
                         
                      • 512Stroker

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

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                        I have an idle solenoid that kicks the idle speed up to near 1000 rpm when the AC is on, helps it idle better and spins the fan another 200 rpm faster.
                         
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                        • 1969383S

                          1969383S FABO Gold Member FABO Gold Member

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                          This is the thinking that got me into trouble in the 1980's!

                          I have the same Engine set-up with the correct pieces today! Over all Timing also dialed in!

                          Yellow Rose, Mattax and RRR are dead on and exactly why my car runs so nice and cool today! High flow in the Pump and Stat and by all means the rest the system needs to be up to it. No stupid flex hoses covered in braid and such. Use the right parts and the ones originally engineered by Chrysler! Then smile and drive! :lol:
                           
                          Last edited: Jun 17, 2021
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                          • Mattax

                            Mattax Just the facts, ma'am FABO Gold Member

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                            I know we're drifting offtopic but those are real nice feature IMO. I don't know when they began using those as regular practice or on which models. Even in '85 AMC Jeep still had not implemented them - but they still seem to have been thinking A/C as mostly a dealer installed option :rolleyes: (even though they offered it both ways).
                             
                          • 512Stroker

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

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                            My
                            Mine is an Edelbrock solenoid that bolts right on to their carb, adjusts really easy.
                             
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                            • ir3333

                              ir3333 Well-Known Member

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                              lots of confusion here but i think AC or trailer towing water pumps were driven faster to increase fan speed to move more air.To compensate the AC and Trailer towing water pumps had fewer vanes at 6 and smaller at 3 1/2".Standard water pump had 8 vanes at 4 3/8". Both pumps moved the same amount of coolant.
                              Probably not a good idea to run without a stat or drill holes in it....or change the fluid speed.Temps at 160 are too cool and will increase engine wear. By '69 195 degree thermostats were stock to reduce emissions and burn more efficiently.
                              I think slant sixes ran a 200 degree thermostat.
                               
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                              • Mattax

                                Mattax Just the facts, ma'am FABO Gold Member

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                                • yellow rose

                                  yellow rose Overnight Sensation FABO Gold Member

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                                  Really? Maybe you should because they started over driving the pumps after 1970 or something. And what they did in no way makes what I posted wrong. And I would argue with anyone claiming what you claim.

                                  It’s beyond idiotic to leave the coolant in the block longer so it can stay in the radiator longer. I even gave you provable examples and yet, you refer to Chrysler engineers. I say grab a FSM and see if they were overdriving the pump. Because they were. And that wasn’t to keep the coolant in the radiator longer.

                                  Or better yet, why don’t you call Griffin radiator and tell them your theory. I suggest they would highly disagree with you.
                                   
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