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Possible overheating problem

Discussion in 'Land Rover Discovery' started by Menash, Sep 3, 2020.

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  1. Stanleysteamer

    Stanleysteamer Well-Known Member

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    I think if his stat was fitted wrong, in the heat he is driving in he'd know about it pretty quickly!
    Tother point is interesting though!
     
  2. triggersbroom

    triggersbroom Active Member

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    My symptoms where similar ran spot on when revs where up but low revs or in traffic she started to get hot changed rad and thermostat to no avail
    Pump was last to change after reading a few posts of impellers breaking free but the coupling came off the ps when the pump was removed
     
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  3. NPG

    NPG Well-Known Member

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    You say you changed the thermostat. Are you sure it's installed the right way round because the symptoms you describe suggest it might not be.
     
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  4. Stanleysteamer

    Stanleysteamer Well-Known Member

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    +1 ^
    Had that once on a Cortina Mk3 previous owner or garage was a tw@t! took a while to work it out though!
     
  5. NPG

    NPG Well-Known Member

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    I read about a few cases where this happened on the TD5, even though the thermostat has markings on it indicating the flow and orientation. I also realise that this was mentioned already by @triggersbroom so sorry for that.

    However, the point I'm trying to make is that if I was the OP, I would go over the work done and make sure that it's 100% before I start pulling other things out. Like checking if the system is properly bled and that the coolant is the correct type (OAT) and mixed in the right proportions. Especially since coolant additives reduce the heat transfer properties of water, maybe the mix has too much coolant in it for such a hot environment.
     
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  6. Menash

    Menash Member

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    I checked the direction of the flow in the thermostat and i am sure this is not the problem.
    I am using caterpillar coolant was recommended by few "old" disco drivers in Israel. I will send a pic. I put only coolant with no water as they recommended.
     

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  7. NPG

    NPG Well-Known Member

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    While I'm not familiar with CAT ELC, the literature does say that it contains nitrites, which in effect makes it a NOAT (Nitrited Organic Acid Technology). This is in contrast with LR's recommended OAT, which is nitrite-free and therefore the chemical composition is not the same. On paper, certain characteristics of CAT ELC do look superior when compared with conventional OAT such as its higher boiling point. What I don't know is if these better specs are in any way affecting the coolant's efficiency to absorb heat at the specified rate, as intended by the D2 design. I know for certain that OAT's performance is drastically reduced if mixed with a nitrite-based coolant and so the question is how much of the original OAT coolant remained in the system before adding CAT ELC.

    The attached image shows a prediluted 50/50 mixture so there was no need to add water as long as the total concentration of coolant in the system does not exceed 60%. Everything considered, you might be OK and the problem could be somewhere else as suggested by other contributors but I personally wouldn't have used a NOAT. As a suggestion, perhaps you might want to replace 1L of coolant with purified water and see if things will improve.
     
  8. Menash

    Menash Member

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    NPG, except dilution with 1 l purified water, witch coolant would you recommend for such hot wather as we got in Israel?
     
  9. Menash

    Menash Member

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    I can say for sure that I replace it for the first time last mount, when i replaced the thermostat and the sistem was empty. I even wash it with few lite water before
     
  10. sierrafery

    sierrafery Well-Known Member

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    Just seen this
    No worries, up to 105*C under load or while climbing at above 35*C ambient temp is perfectly normal especially if you have bigger than standard tyres too...if it goes below 100 while you descend or drive it easy it's no problem
     
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  11. Menash

    Menash Member

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    Thanks sierrafery, your opinion is very important to me
     
  12. NPG

    NPG Well-Known Member

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    The primary cooling agent in engine coolant is water because it's cheap and has excellent heat transfer and thermal capacity properties. All the other chemicals typically found in coolant such as ethylene glycol are added to modify the properties of water (freezing point, boiling point, etc.) and to provide corrosion protection for particular metals such as aluminium. As expected, these additives will also affect the heat absorption rate of water and will in fact reduce the cooling performance. Hence, the more water you have in the mix, the more efficient the heat loss from the engine. Because of this and given your hot climate, I would personally use 33% coolant and the rest just water and replace every 3 years instead of 5. The cooling system operates under pressure and at 1.4 bar (the point when the relief valve on the pressure cap opens), the boiling point is raised from 104°C at 1 bar to around 113°C using conventional OAT at 33% volume. Given that you have CAT ELC, this would be even higher, up to around 130°C. As for the freezing point, I don't think temperatures below -20°C are of concern in Israel.

    I personally use Halfords OAT concentrate but I doubt if this is available where you live. But any standard nitrite-free OAT should do.
     
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  13. NPG

    NPG Well-Known Member

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    And did you have the same issue before you did the change ?
     
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  14. Menash

    Menash Member

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    I had the feeling that my car is getting too hot before checking the fan and replacing the thermostat. That was the reasone i did it. I really don't know if the changes made any difference at all. At least not yet
    I think i will check the rad and then see....
    My mechanic say that i should replace viscous fan and see, and for that o need to buy one...
     
  15. Stanleysteamer

    Stanleysteamer Well-Known Member

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    Without wishing to reignite the viscous fan argument, there is a simple way of testing to see of it comes on or not.
    First do the test i mentioned before, i.e. check it moves relatively freely when the engine is cold, then drive the car till it gets hot, park the car, put the engine off then immediately try the same test, the fan should not move at all.
    Only if it does move, under hand pressure, would I consider replacing it.
     
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  16. sierrafery

    sierrafery Well-Known Member

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    You worry too much, as i said at those temps which you mentioned it's no problem at all, though aybe you'll create some if you insist :cool:
     
  17. NPG

    NPG Well-Known Member

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    If you are sure that it was doing it before you renewed the cooling components, I suggest you either do what Stanley is suggesting or take SF's input on board and keep monitoring the coolant system, especially if your observations of high engine temp were made when humidity was higher than usual. As humidity goes up, air becomes lighter and carries less oxygen molecules. This will impact radiator cooling and the air pressure created by the viscous fan inside the engine bay. You did not mention if you are experiencing reduced performance but the increased water vapor and reduced oxygen in humid air will also effect combustion, i.e. the flame temperature is reduced. I would suspect that the ECU will compensate for this with additional fuel and restricted EGR gases so the engine might be running a little bit hotter for this reason. The MAF sensor is critical for the ECU to correctly adapt to changes in the ambient environment so perhaps it would be a good idea to run some MAF live readings and post them here for discussion.
     
  18. Menash

    Menash Member

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    It is hard for me to evaluate the performance because the my disco is used 100% for trips on weekends and for some reasons (i had a lot of faults lately) i barely drove it for the last 6 mounts. I am afraid my evaluation can misleads me and you....
    About the EGR... i blanked it....
    I can disconnect the MAF and evaluate if it works because i don't have nanocom for the live readings .
    Do you think a small leakage of coolant can cause a reduced pressure and efficiency of the system? If you think so, i have a small leakage i suspect from the coolant pump area- Might worth invastigation
     
  19. sierrafery

    sierrafery Well-Known Member

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    No it can't as long as the tank has coolant in it... i'm telling you for the last time that you worry for nothing at the temps you described in your first post
     
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  20. NPG

    NPG Well-Known Member

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    This could be another reason for the engine temp being a bit higher than normal as the fuel / air mixture contains only oxygen that will produce higher flame temperature.

    You will see a difference in performance if you do that but it's not a conclusive test. So can I ask what tool did you use to read the coolant temp ?

    The thing with a leakage is that if coolant can come out, air can go in and you can end up with an air lock. But this depends how small is small and if it is even noticeable at the coolant level in the expansion tank. Note that the coolant pump has a weep hole, designed to leak coolant which would otherwise end up in the bearing. It would be a very small amount but you'll see the red staining nonetheless. So unless this leak is significant, I wouldn't worry about it.
     
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