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Cooling problems

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  • Cooling problems

    I had a cooling problem in the sense that the coolant was heating up to 4 fast blobs. This was observed today in winter, for 100m of slope the liquid reached 4 blobs.
    Now I slipped the antifreeze, and I replaced it with water a few days ago. Since then I have not touched 4 blobs.
    The antifreeze was Hepu, 50-50.
    I bought a climatic radiator and related plastic frame but I received a cooling engine radiator + clima radiator + fan + expansion vessel + plastic frame, that is all the cooling / air conditioning subassembly.
    Only by changing the coolant the cooling system started to function in normal parameters - it results that the antifreeze was bad.
    Anyway we will also prepare a thermostat with element 06H121113B that is credited with 95C but has the larger diameter so a smaller opening generates the same flow section.
    The water will be replaced with Mobil Antifreeze Extra G11
    Mercedes recommends Smart 450 anti-freeze with MB325.0 standard.
    What do you think about all this?

  • #2
    Are you sure that it wasn't an air block somewhere in the system? It sounds quite bizarre that a mix of antifreeze and water would be massively less effective than water itself. I had a massive problem with air blockage after engine re-bulid and it is a PITA to bleed 450 properly


    • #3
      Normal reasons why it goes to 4 blobs quickly:-

      Air blockage
      Water pump not circulating fluid properly.



      • #4
        Air in the system was not because I blew the system before lowering the antifreeze. After bleeding no results.
        Rather counterfeited antifreeze because we are not analytical laboratories; the vast majority of products found here (in Ro) are of dubious quality.
        May be the water pump but why with antifreeze operation is problematic, with water works well?

        What do you think about all this?


        • #5
          As far as I understand.....
          Antifreeze is replaced as the corrosion inhibitor element depletes.
          Two types exist (identified by colour) and better kept separate.

          Watch that the new thermostat doesn't open so suddenly as to cause a 'cold' seizure (where cold water introduced suddenly to a hot block causes the block to contract onto hot expanded pistons).


          • mottofreee
            mottofreee commented
            Editing a comment
            We chose a higher thermostat opening temperature because the thermostat is also bigger.

          • Thrumbleux
            Thrumbleux commented
            Editing a comment
            That compounds it.
            Block at higher temp before thermostat opens, then bigger volume of cold water delivered more quickly.

          • mottofreee
            mottofreee commented
            Editing a comment
            The wax thermostat is analogous, has several positions - closed 0 ... 100%.
            However his movement is slow, his opening is not sudden. Indeed there is a risk of thermal shock, Smart450CDI has small circuit without thermostat for shock prevention.
            The selected thermostat has a full opening need of 105C and operates at 95C. The cross section is 15cm2 at 95C and OE Smart is 9.5cm2 at 90C.
            From my estimates, the new thermostat will open at 90C 2/3 max, ie the same as OE.

            The deformed cylinder from thermal shock has met but only due to certain conditions: added very cold - fresh spring water - water to the overheated engine (overheating due to lack of coolant).

        • #6
          The antifreeze with which the car came from the previous owner was still red (G12), but it was dirty - opaque.
          I washed the water cooling circuit, drained and dipped the circuit.
          After that we introduced the Hepu G12 antifreeze concentrate. Dilution 50-50 with distilled water.
          Past days I drained Hepu, which was transparent, clean. Now circulating with water just to wash the entire system because I want to put Mobile Anti Freeze Extra G11 which is another color; respect the color coding of antifreeze types in the sense that different colors are not mixed in any way.
          Last edited by mottofreee; 13-06-18, 12:23 PM.


          • #7
            We (smart specialist and many more smart drivers in the Netherlands) put normal coolant in our smarts (or in other cars) never have problems with the fluid .
            Some aftermarket thermostat and waterpumps , can give some trouble like 4 bolbs /100 degrees


            • #8
              I use Google Translate ,which is a powerful tool but only translates the words.
              With this car circulating for 3 years.
              I replaced the antifreeze 2 years ago with Hepu @ -37C.
              That winter I noticed that the antifreeze overheats.
              Now I dropped the antifreeze and put the water. Overheating has passed with the antifreeze. With the water no longer overheating - in 300km it has only reached 3 blobs.
              In the next few weeks I will undo the radiator package and then it will
              recondition the water heater (blown, washed, straightened).
              Obviously the antifreeze caused overheating. What I do not know is what caused this, I suspect that the antifreeze is fake or ...? What is the reason a liquid loses its heat transfer capacity?


              • #9
                You are wasting time and money changing your Hepu G12 coolant. There is nothing wrong with Hepu G12. A good German coolant suitable for aluminium engines.

                Hepu G12
                New-generation long life coolant additive with silicon additive package. This full concentrate engine coolant offers excellent protection against frost, over-heating, corrosion and scaling. Free from borate, nitrite, amine and phosphates and particularly recommended for light-metal engines which demand special aluminum protection at higher temperatures.



                • #10
                  Hepu was two years old in the engine, anyway, it had to be changed soon.
                  At the same time he was consumed for the change (now or in the future) and as money we spent 15 pounds a year earlier.
                  I will use the antifreeze recommended by the manufacturer (MB 325.0) blue (with silicates).
                  The question "why cooling fluids lose the heat transmission quality?" it remains.
                  Water has more specific heat than antifreeze (@ -37C).
                  What is the specific heat of the ready-mix antifreeze?


                  • #11
                    Originally posted by mottofreee View Post
                    The question "why cooling fluids lose the heat transmission quality?" it remains.
                    Possibly, the depletion of corrosion inhibitor properties would lead to corrosion/scaling of the water galleries forming an insulating layer between coolant and metal. In your case though, the coolant is absorbing heat - it is dissipating it that is the problem, suggesting any corrosion/scaling is in the radiator (or has that just been replaced with new?)
                    Without knowing the history of your car it's impossible to say that is what has happened here. Could raw water be compensating if the above has occurred? What will happen when an antifreeze/water mix is reinstated?


                    • #12
                      The radiator, water pump, pump belt, thermostat are those from the introduction of the Hepu antifreeze. Nothing has been replaced at this time.
                      There are no deposits on the circuit (I did not see, at inspection).
                      Probably the additives have been consumed before the weather, but the physical heat transfer properties of the antifreeze do not depend on them. When I replace water (with antifreeze), I do not know what it will be - of course I hope the cooling system works in parameters.

                      With the fan on the radiator turned on, it hardly rinsed (from 4 blobs to 3).
                      I do not use aircon!
                      In my opinion the antifreeze was not appropriate although theoretically it was supposed to be. What could have degraded the antifreeze so quickly?


                      • #13
                        Originally posted by mottofreee View Post
                        Water has more specific heat than antifreeze (@ -37C).
                        OK, if water is better than antifreeze as a coolant and we consider that pure water is allowing your engine to operate at correct temperature but using antifreeze causes a marginal problem to manifest itself - then that 'problem' could be anywhere.That is, it isn't the antifreeze that is the problem, it is merely showing up a physical problem elsewhere.

                        These cars cooling system do degrade with age I think. On mine, the fast idle emissions test at MOT never raised the gauge to 4 blobs but it has the last two MOT tests. Admittedly they have been in slightly warmer weather but when I observe the flattened fins on the radiator cores near the bottom, I'm apt to consider that the problem lies there.


                        • #14
                          A malfunction elsewhere.
                          Since the system has returned to good functioning just by changing the fluid, what could be the problem?
                          Again, please note that only fluid was changed - this is the reason for which puzzled.


                          • #15
                            Originally posted by mottofreee View Post
                            Since the system has returned to good functioning just by changing the fluid, what could be the problem?
                            Do you have figures for specific heat for water and for antifreeze (glycol?)?
                            If the two numbers differ significantly (in water's favour) then my theory may be correct. And if so, reinstating antifreeze will cause the temperature to go high again.
                            If the two numbers are very close - then something of a mystery. When do you plan to refill with antifreeze mix?


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